diff --git a/eq-author-api/constants/validationErrorCodes.js b/eq-author-api/constants/validationErrorCodes.js
index 1b549dd0a4..880f769b32 100644
--- a/eq-author-api/constants/validationErrorCodes.js
+++ b/eq-author-api/constants/validationErrorCodes.js
@@ -38,6 +38,7 @@ const ERR_COUNT_OF_GREATER_THAN_AVAILABLE_OPTIONS =
 const ERR_VALID_PIPED_ANSWER_REQUIRED = "ERR_VALID_PIPED_ANSWER_REQUIRED";
 const ERR_UNIQUE_PAGE_DESCRIPTION = "ERR_UNIQUE_PAGE_DESCRIPTION";
 const ERR_NO_ANSWERS = "ERR_NO_ANSWERS";
+const ERR_SURVEY_ID_MISMATCH = "ERR_SURVEY_ID_MISMATCH";
 
 module.exports = {
   ERR_INVALID,
@@ -76,4 +77,5 @@ module.exports = {
   ERR_VALID_PIPED_ANSWER_REQUIRED,
   ERR_UNIQUE_PAGE_DESCRIPTION,
   ERR_NO_ANSWERS,
+  ERR_SURVEY_ID_MISMATCH,
 };
diff --git a/eq-author-api/src/validation/customKeywords/index.js b/eq-author-api/src/validation/customKeywords/index.js
index 4c325b9007..ec77ba8e42 100644
--- a/eq-author-api/src/validation/customKeywords/index.js
+++ b/eq-author-api/src/validation/customKeywords/index.js
@@ -5,6 +5,7 @@ module.exports = (ajv) => {
   require("./calculatedSummaryPosition")(ajv);
   require("./validateLatestAfterEarliest")(ajv);
   require("./validateDuration")(ajv);
+  require("./validateSurveyId")(ajv);
   require("./validateMultipleChoiceCondition")(ajv);
   require("./validateExpression")(ajv);
   require("./validateRoutingDestination")(ajv);
diff --git a/eq-author-api/src/validation/customKeywords/validateSurveyId.js b/eq-author-api/src/validation/customKeywords/validateSurveyId.js
new file mode 100644
index 0000000000..c3853d86ad
--- /dev/null
+++ b/eq-author-api/src/validation/customKeywords/validateSurveyId.js
@@ -0,0 +1,42 @@
+const createValidationError = require("../createValidationError");
+const {
+  ERR_SURVEY_ID_MISMATCH,
+} = require("../../../constants/validationErrorCodes");
+
+module.exports = (ajv) =>
+  ajv.addKeyword({
+    keyword: "validateSurveyId",
+    validate: function isValid(
+      _schema,
+      questionnaireSurveyId, // gives the data entered into the survey ID field
+      _parentSchema,
+      {
+        instancePath, // gives the path /surveyId
+        rootData: questionnaire, // gives the whole questionnaire object
+        parentDataProperty: fieldName, // gives the field name surveyId
+      }
+    ) {
+      // Get the supplementary data from the questionnaire object
+      const supplementaryData = questionnaire.supplementaryData;
+
+      // If supplementaryData exists and contains a surveyId, and supplementaryData's surveyId doesn't match the questionnaire's surveyId, throw a validation error
+      if (
+        supplementaryData &&
+        supplementaryData.surveyId &&
+        questionnaireSurveyId !== supplementaryData.surveyId
+      ) {
+        isValid.errors = [
+          createValidationError(
+            instancePath,
+            fieldName,
+            ERR_SURVEY_ID_MISMATCH,
+            questionnaire,
+            ERR_SURVEY_ID_MISMATCH
+          ),
+        ];
+        return false;
+      }
+
+      return true;
+    },
+  });
diff --git a/eq-author-api/src/validation/schemas/questionnaire.json b/eq-author-api/src/validation/schemas/questionnaire.json
index 77a6bde3d1..85b46ca871 100644
--- a/eq-author-api/src/validation/schemas/questionnaire.json
+++ b/eq-author-api/src/validation/schemas/questionnaire.json
@@ -26,18 +26,25 @@
       "$ref": "submission.json"
     },
     "surveyId": {
-      "if": {
-        "type": "string",
-        "minLength": 1
-      },
-      "then": {
-        "type": "string",
-        "pattern": "^\\d{3}$",
-        "errorMessage": "ERR_INVALID"
-      },
-      "else": {
-        "$ref": "definitions.json#/definitions/populatedString"
-      }
+      "allOf": [
+        {
+          "if": {
+            "type": "string",
+            "minLength": 1
+          },
+          "then": {
+            "type": "string",
+            "pattern": "^\\d{3}$",
+            "errorMessage": "ERR_INVALID"
+          },
+          "else": {
+            "$ref": "definitions.json#/definitions/populatedString"
+          }
+        },
+        {
+          "validateSurveyId": true
+        }
+      ]
     },
     "formType": {
       "if": {
diff --git a/eq-author/src/constants/validationMessages.js b/eq-author/src/constants/validationMessages.js
index 5c8013063a..c305e700b6 100644
--- a/eq-author/src/constants/validationMessages.js
+++ b/eq-author/src/constants/validationMessages.js
@@ -346,6 +346,8 @@ export const destinationErrors = {
 export const SURVEY_ID_ERRORS = {
   ERR_VALID_REQUIRED: "Enter a survey ID",
   ERR_INVALID: "Enter a survey ID in the correct format",
+  ERR_SURVEY_ID_MISMATCH:
+    "The survey ID does not match the linked supplementary data schema",
 };
 
 export const FORM_TYPE_ERRORS = {