diff --git a/app/uk/gov/hmrc/apiplatformoutboundsoap/controllers/ConfirmationController.scala b/app/uk/gov/hmrc/apiplatformoutboundsoap/controllers/ConfirmationController.scala
index d4274cc..51b041f 100644
--- a/app/uk/gov/hmrc/apiplatformoutboundsoap/controllers/ConfirmationController.scala
+++ b/app/uk/gov/hmrc/apiplatformoutboundsoap/controllers/ConfirmationController.scala
@@ -40,11 +40,15 @@ class ConfirmationController @Inject()(cc: ControllerComponents,
     val xml: NodeSeq = request.body
 
     def callService(deliveryStatus: DeliveryStatus, id: String): Future[Result] = {
-      confirmationService.processConfirmation(xml, id, deliveryStatus) map {
-        case NoContentUpdateResult => NoContent
-        case _ =>
-          logger.warn(s"No message found with global ID [$id]. Request is ${xml}")
-          NotFound
+      if(id.trim.nonEmpty) {
+        confirmationService.processConfirmation(xml, id.trim, deliveryStatus) map {
+          case NoContentUpdateResult => NoContent
+          case _ =>
+            logger.warn(s"No message found with global ID [$id]. Request is ${xml}")
+            NotFound
+        }
+      } else {
+        Future.successful(BadRequest)
       }
     }
 
diff --git a/test/uk/gov/hmrc/apiplatformoutboundsoap/controllers/ConfirmationControllerSpec.scala b/test/uk/gov/hmrc/apiplatformoutboundsoap/controllers/ConfirmationControllerSpec.scala
index 3c8302d..e2c4d5f 100644
--- a/test/uk/gov/hmrc/apiplatformoutboundsoap/controllers/ConfirmationControllerSpec.scala
+++ b/test/uk/gov/hmrc/apiplatformoutboundsoap/controllers/ConfirmationControllerSpec.scala
@@ -44,7 +44,7 @@ class ConfirmationControllerSpec extends AnyWordSpec with Matchers with GuiceOne
 
   "message" should {
     val fakeRequest = FakeRequest("POST", "/acknowledgement")
-    val codMessage: String =
+    def createCodMessage(relatesTo: String) = {
       """<?xml version="1.0" encoding="UTF-8" standalone="no"?>
         |<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:ccn2="http://ccn2.ec.eu/CCN2.Service.Platform.Acknowledgement.Schema">
         |    <soap:Header xmlns:wsa="http://www.w3.org/2005/08/addressing">
@@ -52,7 +52,7 @@ class ConfirmationControllerSpec extends AnyWordSpec with Matchers with GuiceOne
         |        <wsa:From>
         |            <wsa:Address>[FROM]</wsa:Address>
         |        </wsa:From>
-        |        <wsa:RelatesTo RelationshipType="http://ccn2.ec.eu/addressing/ack">1234abcd</wsa:RelatesTo>
+        |        <wsa:RelatesTo RelationshipType="http://ccn2.ec.eu/addressing/ack">[RELATES_TO]</wsa:RelatesTo>
         |        <wsa:MessageID>[COD_MESSAGE_ID]</wsa:MessageID>
         |        <wsa:To>[TO]</wsa:To>
         |    </soap:Header>
@@ -62,6 +62,8 @@ class ConfirmationControllerSpec extends AnyWordSpec with Matchers with GuiceOne
         |        </ccn2:CoD>
         |    </soap:Body>
         |</soap:Envelope>""".stripMargin.replaceAll("\n", "")
+        .replaceAll("\\[RELATES_TO]", relatesTo)
+    }
 
     val codMessageWithNoRelatesTo =
       """<?xml version="1.0" encoding="UTF-8" standalone="no"?>
@@ -123,7 +125,7 @@ class ConfirmationControllerSpec extends AnyWordSpec with Matchers with GuiceOne
       val confirmationXmlRequestCaptor = ArgumentCaptor.forClass(classOf[NodeSeq])
       val msgIdCaptor = ArgumentCaptor.forClass(classOf[String])
       val confirmationTypeCaptor = ArgumentCaptor.forClass(classOf[DeliveryStatus])
-      val requestBodyXml: Elem = XML.loadString(codMessage)
+      val requestBodyXml: Elem = XML.loadString(createCodMessage("1234abcd"))
        when(confirmationServiceMock.processConfirmation(confirmationXmlRequestCaptor.capture, msgIdCaptor.capture(), confirmationTypeCaptor.capture)(*))
         .thenReturn(Future.successful(NoContentUpdateResult))
       val result: Future[Result] = underTest.message()(fakeRequest.withBody(requestBodyXml)
@@ -144,6 +146,16 @@ class ConfirmationControllerSpec extends AnyWordSpec with Matchers with GuiceOne
       verifyZeroInteractions(confirmationServiceMock)
     }
 
+    "return 400 when exists an XML request with blank, whitespaces, newline and tab space in RelatesTo element" in new Setup {
+      Seq("", "  ", "\n", "\t") foreach { relatesTo =>
+        val requestBodyXml: Elem = XML.loadString(createCodMessage(relatesTo))
+        val result: Future[Result] = underTest.message()(fakeRequest.withBody(requestBodyXml)
+          .withHeaders("ContentType" -> "text/xml", "x-soap-action" -> "CCN2.Service.Platform.AcknowledgementService/CoD"))
+        status(result) shouldBe BAD_REQUEST
+        verifyZeroInteractions(confirmationServiceMock)
+      }
+    }
+
     "call the confirmation service with a CoE request" in new Setup {
       val confirmationXmlRequestCaptor = ArgumentCaptor.forClass(classOf[NodeSeq])
       val msgIdCaptor = ArgumentCaptor.forClass(classOf[String])
@@ -170,14 +182,14 @@ class ConfirmationControllerSpec extends AnyWordSpec with Matchers with GuiceOne
     }
 
     "handle receiving a request with an invalid SOAP action" in new Setup {
-      val result: Future[Result] = underTest.message()(fakeRequest.withBody(XML.loadString(codMessage))
+      val result: Future[Result] = underTest.message()(fakeRequest.withBody(XML.loadString(createCodMessage("1234abcd")))
         .withHeaders("ContentType" -> "text/xml", "x-soap-action" -> "foobar"))
       status(result) shouldBe BAD_REQUEST
       verifyZeroInteractions(confirmationServiceMock)
     }
 
     "handle receiving a request with no x-soap-action header" in new Setup {
-      val result: Future[Result] = underTest.message()(fakeRequest.withBody(XML.loadString(codMessage))
+      val result: Future[Result] = underTest.message()(fakeRequest.withBody(XML.loadString(createCodMessage("1234abcd")))
         .withHeaders("ContentType" -> "text/xml"))
       status(result) shouldBe BAD_REQUEST
       verifyZeroInteractions(confirmationServiceMock)