diff --git a/module/Olcs/src/Controller/ConversationsController.php b/module/Olcs/src/Controller/ConversationsController.php
index 92185cc4b..f027cf303 100644
--- a/module/Olcs/src/Controller/ConversationsController.php
+++ b/module/Olcs/src/Controller/ConversationsController.php
@@ -7,14 +7,18 @@
 use Common\Controller\Interfaces\ToggleAwareInterface;
 use Common\Controller\Lva\AbstractController;
 use Common\FeatureToggle;
+use Common\Form\Form;
 use Common\Service\Helper\FlashMessengerHelperService;
+use Common\Service\Helper\FormHelperService;
 use Common\Service\Table\TableFactory;
+use Dvsa\Olcs\Transfer\Command\Messaging\Message\Create as CreateMessageCommand;
 use Dvsa\Olcs\Transfer\Query\Messaging\Messages\ByConversation as ByConversationQuery;
 use Dvsa\Olcs\Transfer\Query\Messaging\Conversations\ByOrganisation as ByOrganisationQuery;
 use Dvsa\Olcs\Utils\Translation\NiTextTranslation;
+use Laminas\Http\Response;
 use Laminas\View\Model\ViewModel;
-use Laminas\View\View;
 use LmcRbacMvc\Service\AuthorizationService;
+use Olcs\Form\Model\Form\Message\Reply as ReplyForm;
 
 class ConversationsController extends AbstractController implements ToggleAwareInterface
 {
@@ -25,17 +29,19 @@ class ConversationsController extends AbstractController implements ToggleAwareI
     ];
 
     protected FlashMessengerHelperService $flashMessengerHelper;
-    protected TableFactory                $tableFactory;
+    protected TableFactory $tableFactory;
+    protected FormHelperService $formHelperService;
 
     public function __construct(
-        NiTextTranslation           $niTextTranslationUtil,
-        AuthorizationService        $authService,
+        NiTextTranslation $niTextTranslationUtil,
+        AuthorizationService $authService,
         FlashMessengerHelperService $flashMessengerHelper,
-        TableFactory                $tableFactory
-    )
-    {
+        TableFactory $tableFactory,
+        FormHelperService $formHelperService
+    ) {
         $this->flashMessengerHelper = $flashMessengerHelper;
         $this->tableFactory = $tableFactory;
+        $this->formHelperService = $formHelperService;
 
         parent::__construct($niTextTranslationUtil, $authService);
     }
@@ -77,7 +83,8 @@ public function addAction(): ViewModel
         return $view;
     }
 
-    public function viewAction(): ViewModel
+    /** @return ViewModel|Response */
+    public function viewAction()
     {
         $params = [
             'page'         => $this->params()->fromQuery('page', 1),
@@ -95,12 +102,53 @@ public function viewAction(): ViewModel
             $messages = [];
         }
 
+        $form = $this->formHelperService->createForm(ReplyForm::class, true, false);
+        $this->formHelperService->setFormActionFromRequest($form, $this->getRequest());
+
         $table = $this->tableFactory
             ->buildTable('messages-view', $messages, $params);
 
-        $view = new ViewModel(['table' => $table]);
+        $view = new ViewModel(
+            [
+                'table' => $table,
+                'form'  => $form,
+            ],
+        );
         $view->setTemplate('messages-view');
 
+        if ($this->getRequest()->isPost() && $this->params()->fromPost('action') === 'reply') {
+            return $this->parseReply($view, $form);
+        }
+
         return $view;
     }
+
+    /** @return Response|ViewModel */
+    protected function parseReply(ViewModel $view, Form $form)
+    {
+        $form->setData((array)$this->params()->fromPost());
+        $form->get('id')->setValue($this->params()->fromRoute('conversation'));
+
+        if (!$form->isValid()) {
+            return $view;
+        }
+
+        $response = $this->handleCommand(
+            CreateMessageCommand::create(
+                [
+                    'conversation'   => $this->params()->fromRoute('conversationId'),
+                    'messageContent' => $form->get('form-actions')->get('reply')->getValue(),
+                ],
+            ),
+        );
+
+        if ($response->isOk()) {
+            $this->flashMessengerHelper->addSuccessMessage('Reply submitted successfully');
+            return $this->redirect()->toRoute('conversations/view', $this->params()->fromRoute());
+        }
+
+        $this->handleErrors($response->getResult());
+
+        return parent::indexAction();
+    }
 }
diff --git a/module/Olcs/src/Controller/Factory/ConversationsControllerFactory.php b/module/Olcs/src/Controller/Factory/ConversationsControllerFactory.php
index ec05a471f..96e6cb6ad 100644
--- a/module/Olcs/src/Controller/Factory/ConversationsControllerFactory.php
+++ b/module/Olcs/src/Controller/Factory/ConversationsControllerFactory.php
@@ -5,6 +5,7 @@
 namespace Olcs\Controller\Factory;
 
 use Common\Service\Helper\FlashMessengerHelperService;
+use Common\Service\Helper\FormHelperService;
 use Common\Service\Table\TableFactory;
 use Dvsa\Olcs\Utils\Translation\NiTextTranslation;
 use Interop\Container\ContainerInterface;
@@ -15,18 +16,23 @@
 
 class ConversationsControllerFactory implements FactoryInterface
 {
-    public function __invoke(ContainerInterface $container, $requestedName, array $options = null): ConversationsController
-    {
+    public function __invoke(
+        ContainerInterface $container,
+        $requestedName,
+        array $options = null
+    ): ConversationsController {
         $niTextTranslationUtil = $container->get(NiTextTranslation::class);
         $authService = $container->get(AuthorizationService::class);
         $flashMessengerHelper = $container->get(FlashMessengerHelperService::class);
         $tableFactory = $container->get(TableFactory::class);
+        $formHelperService = $container->get(FormHelperService::class);
 
         return new ConversationsController(
             $niTextTranslationUtil,
             $authService,
             $flashMessengerHelper,
             $tableFactory,
+            $formHelperService,
         );
     }
 }
diff --git a/module/Olcs/src/Form/Model/Fieldset/Message/Reply.php b/module/Olcs/src/Form/Model/Fieldset/Message/Reply.php
new file mode 100644
index 000000000..debb24e15
--- /dev/null
+++ b/module/Olcs/src/Form/Model/Fieldset/Message/Reply.php
@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Olcs\Form\Model\Fieldset\Message;
+
+use Common\Form\Elements\InputFilters\ActionButton;
+use Laminas\Form\Annotation as Form;
+use Laminas\Form\Element\File;
+use Laminas\Form\Element\Textarea;
+
+class Reply
+{
+    /**
+     * @Form\Attributes({
+     *     "class": "extra-long",
+     *     "maxlength": 1000
+     * })
+     * @Form\Options({"label": "You can enter up to 1000 characters"})
+     * @Form\Required(true)
+     * @Form\Type(\Laminas\Form\Element\Textarea::class)
+     * @Form\Filter({"name": \Laminas\Filter\StringTrim::class})
+     * @Form\Validator({
+     *     "name": \Laminas\Validator\StringLength::class,
+     *     "options": {"max":1000}
+     * })
+     */
+    public ?TextArea $reply = null;
+
+    /**
+     * @Form\Attributes({
+     *     "type": "submit",
+     *     "data-module": "govuk-button",
+     *     "class": "govuk-button govuk-button--default",
+     *     "id": "send"
+     * })
+     * @Form\Options({
+     *     "label": "Send message"
+     * })
+     * @Form\Type(\Common\Form\Elements\InputFilters\ActionButton::class)
+     */
+    public ?ActionButton $send = null;
+}
diff --git a/module/Olcs/src/Form/Model/Form/Message/Reply.php b/module/Olcs/src/Form/Model/Form/Message/Reply.php
new file mode 100644
index 000000000..a4f6a83bc
--- /dev/null
+++ b/module/Olcs/src/Form/Model/Form/Message/Reply.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Olcs\Form\Model\Form\Message;
+
+use Laminas\Form\Annotation as Form;
+use Laminas\Form\Element\Hidden;
+use Olcs\Form\Model\Fieldset\Message\Reply as ReplyFieldset;
+
+/**
+ * @codeCoverageIgnore No methods
+ * @Form\Name("licence_message_reply")
+ * @Form\Attributes({"method": "post"})
+ * @Form\Type(\Common\Form\Form::class)
+ * @Form\Options({"prefer_form_input_filter": true})
+ */
+class Reply
+{
+    /**
+     * @Form\Attributes({"value": ""})
+     * @Form\Type(\Laminas\Form\Element\Hidden::class)
+     */
+    public ?Hidden $id = null;
+
+    /**
+     * @Form\Attributes({"value": "reply"})
+     * @Form\Type(\Laminas\Form\Element\Hidden::class)
+     */
+    public ?Hidden $action = null;
+
+    /**
+     * @Form\Name("form-actions")
+     * @Form\ComposedObject(\Olcs\Form\Model\Fieldset\Message\Reply::class)
+     */
+    public ?ReplyFieldset $formActions = null;
+}
diff --git a/module/Olcs/view/messages-view.phtml b/module/Olcs/view/messages-view.phtml
index ebf36dea3..db5596f43 100644
--- a/module/Olcs/view/messages-view.phtml
+++ b/module/Olcs/view/messages-view.phtml
@@ -18,7 +18,21 @@ echo $this->partial(
     echo $menu->setMinDepth(0)
               ->setMaxDepth(0)
               ->setPartial('partials/tabs-nav');
-
+    ?>
+    <details class="govuk-details" data-module="govuk-details">
+      <summary class="govuk-details__summary" aria-controls="details-content-operating-centre">
+        <span class="govuk-details__summary-text">
+            Send a reply
+        </span>
+      </summary>
+      <div class="govuk-details__text" id="details-content-operating-centre">
+        <?php
+        echo $this->formErrors($this->form);
+        echo $this->form($this->form);
+        ?>
+      </div>
+    </details>
+    <?php
     echo $this->table;
     ?>
   </div>
diff --git a/test/Olcs/src/Controller/ConversationsControllerTest.php b/test/Olcs/src/Controller/ConversationsControllerTest.php
index 19da55ecd..d37c63e44 100644
--- a/test/Olcs/src/Controller/ConversationsControllerTest.php
+++ b/test/Olcs/src/Controller/ConversationsControllerTest.php
@@ -2,16 +2,26 @@
 
 namespace OlcsTest\Controller;
 
+use Common\Controller\Plugin\HandleCommand;
 use Common\Controller\Plugin\HandleQuery;
+use Common\Controller\Plugin\Redirect;
+use Common\Form\Form;
 use Common\Service\Cqrs\Response;
 use Common\Service\Helper\FlashMessengerHelperService;
+use Common\Service\Helper\FormHelperService;
 use Common\Service\Table\TableFactory;
 use Dvsa\Olcs\Utils\Translation\NiTextTranslation;
+use Laminas\Form\Element\Text;
+use Laminas\Form\Fieldset;
+use Laminas\Http\Request;
+use Laminas\Http\Response as HttpResponse;
 use Laminas\Mvc\Controller\Plugin\Params;
+use Dvsa\Olcs\Transfer\Command\Messaging\Message\Create as CreateMessageCommand;
 use Laminas\View\Model\ViewModel;
 use Mockery as m;
 use Mockery\Adapter\Phpunit\MockeryTestCase as TestCase;
 use Olcs\Controller\ConversationsController as Sut;
+use Olcs\Form\Model\Form\Message\Reply;
 use ReflectionClass;
 use LmcRbacMvc\Service\AuthorizationService;
 
@@ -25,6 +35,9 @@ public function setUp(): void
         $this->mockAuthService = m::mock(AuthorizationService::class)->makePartial();
         $this->mockFlashMessengerHelper = m::mock(FlashMessengerHelperService::class)->makePartial();
         $this->mockTableFactory = m::mock(TableFactory::class)->makePartial();
+        $this->mockFormHelperService = m::mock(FormHelperService::class)->makePartial();
+        $this->mockForm = m::mock(Form::class);
+        $this->mockParams = m::mock(Params::class);
 
         $this->sut = m::mock(Sut::class)
                       ->makePartial()
@@ -35,6 +48,21 @@ public function setUp(): void
         $this->setMockedProperties($reflectionClass, 'authService', $this->mockAuthService);
         $this->setMockedProperties($reflectionClass, 'flashMessengerHelper', $this->mockFlashMessengerHelper);
         $this->setMockedProperties($reflectionClass, 'tableFactory', $this->mockTableFactory);
+        $this->setMockedProperties($reflectionClass, 'formHelperService', $this->mockFormHelperService);
+
+        $this->mockFormHelperService->shouldReceive('createForm')
+                                    ->once()
+                                    ->with(Reply::class, true, false)
+                                    ->andReturn($this->mockForm);
+
+        $this->mockFormHelperService->shouldReceive('setFormActionFromRequest')
+                                    ->once()
+                                    ->withArgs(
+                                        function ($form, $request) {
+                                            $this->assertInstanceOf(Form::class, $form);
+                                            return true;
+                                        },
+                                    );
     }
 
     public function setMockedProperties(ReflectionClass $reflectionClass, string $property, $value): void
@@ -57,22 +85,21 @@ public function testViewAction(): void
         $mockHandleQuery->shouldReceive('__invoke')
                         ->andReturn($mockResponse);
 
-        $mockParams = m::mock(Params::class);
-        $mockParams->shouldReceive('fromQuery')
-                   ->with('page', 1)
-                   ->andReturn(1);
-        $mockParams->shouldReceive('fromQuery')
-                   ->with('limit', 10)
-                   ->andReturn(10);
-        $mockParams->shouldReceive('fromQuery')
-                   ->withNoArgs()
-                   ->andReturn([]);
-        $mockParams->shouldReceive('fromRoute')
-                   ->with('conversationId')
-                   ->andReturn(1);
+        $this->mockParams->shouldReceive('fromQuery')
+                         ->with('page', 1)
+                         ->andReturn(1);
+        $this->mockParams->shouldReceive('fromQuery')
+                         ->with('limit', 10)
+                         ->andReturn(10);
+        $this->mockParams->shouldReceive('fromQuery')
+                         ->withNoArgs()
+                         ->andReturn([]);
+        $this->mockParams->shouldReceive('fromRoute')
+                         ->with('conversationId')
+                         ->andReturn(1);
 
         $this->sut->shouldReceive('params')
-                  ->andReturn($mockParams);
+                  ->andReturn($this->mockParams);
         $this->sut->shouldReceive('plugin')
                   ->with('handleQuery')
                   ->andReturn($mockHandleQuery);
@@ -91,4 +118,109 @@ public function testViewAction(): void
         $this->assertInstanceOf(ViewModel::class, $view);
         $this->assertEquals($table, $view->getVariable('table'));
     }
+
+    public function testReply(): void
+    {
+        $mockRequest = m::mock(Request::class);
+        $mockRequest->shouldReceive('isPost')
+                    ->once()
+                    ->andReturn(true);
+
+        $this->mockParams->shouldReceive('fromPost')
+                         ->once()
+                         ->with('action')
+                         ->andReturn('reply');
+        $this->mockParams->shouldReceive('fromPost')
+                         ->once()
+                         ->withNoArgs()
+                         ->andReturn(['a' => 'b']);
+        $this->mockParams->shouldReceive('fromRoute')
+                         ->once()
+                         ->with('conversation')
+                         ->andReturn('1');
+        $this->mockParams->shouldReceive('fromRoute')
+                         ->once()
+                         ->withNoArgs()
+                         ->andReturn(['a' => 'b']);
+
+        $this->sut->shouldReceive('getRequest')
+                  ->twice()
+                  ->andReturn($mockRequest);
+
+        $mockCommandReturn = m::mock(Response::class);
+        $mockCommandReturn->shouldReceive('isOk')
+                          ->once()
+                          ->andReturn(true);
+
+        $mockCommandHandler = m::mock(HandleCommand::class);
+        $mockCommandHandler->shouldReceive('__invoke')
+                           ->once()
+                           ->withArgs(
+                               function ($command) {
+                                   $this->assertInstanceOf(CreateMessageCommand::class, $command);
+
+                                   return true;
+                               },
+                           )
+                           ->andReturn($mockCommandReturn);
+
+        $this->sut->shouldReceive('plugin')
+                  ->with('handleCommand')
+                  ->andReturn($mockCommandHandler);
+
+        $this->mockForm->shouldReceive('setData')
+                       ->once()
+                       ->with(['a' => 'b']);
+
+        $mockFormElement = m::mock(Text::class);
+        $mockFormElement->shouldReceive('setValue')
+                        ->once()
+                        ->with('1');
+        $mockFormElement->shouldReceive('getValue')
+                        ->once()
+                        ->andReturn('abc');
+
+        $this->mockForm->shouldReceive('get')
+                       ->once()
+                       ->with('id')
+                       ->andReturn($mockFormElement);
+
+        $mockFormActionsElement = m::mock(Fieldset::class);
+        $mockFormActionsElement->shouldReceive('get')
+                               ->once()
+                               ->with('reply')
+                               ->andReturn($mockFormElement);
+        $this->mockForm->shouldReceive('get')
+                       ->once()
+                       ->with('form-actions')
+                       ->andReturn($mockFormActionsElement);
+
+        $this->mockForm->shouldReceive('isValid')
+                       ->once()
+                       ->with()
+                       ->andReturn(true);
+
+        $this->mockFlashMessengerHelper->shouldReceive('addSuccessMessage')
+                                       ->once()
+                                       ->with('Reply submitted successfully');
+
+        $mockViewModel = m::mock(ViewModel::class);
+        $mockViewModel->shouldReceive('getVariable')
+                      ->once()
+                      ->with('table')
+                      ->andReturn('<table/>');
+
+        $mockRedirect = m::mock(Redirect::class);
+        $mockRedirect->shouldReceive('toRoute')
+                     ->once()
+                     ->with('conversations/view', ['a' => 'b'])
+                     ->andReturn($mockViewModel);
+
+        $this->sut->shouldReceive('plugin')
+                  ->once()
+                  ->with('redirect')
+                  ->andReturn($mockRedirect);
+
+        $this->testViewAction();
+    }
 }