diff --git a/package-lock.json b/package-lock.json
index 6f903eded..ec28b4194 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -11,7 +11,7 @@
       "license": "SEE LICENSE IN LICENSE",
       "dependencies": {
         "@aws-sdk/client-sns": "^3.911.0",
-        "@defra/forms-engine-plugin": "^3.0.9",
+        "@defra/forms-engine-plugin": "^4.0.1",
         "@defra/forms-model": "^3.0.563",
         "@defra/hapi-tracing": "^1.28.0",
         "@elastic/ecs-pino-format": "^1.5.0",
@@ -2914,13 +2914,13 @@
       }
     },
     "node_modules/@defra/forms-engine-plugin": {
-      "version": "3.0.9",
-      "resolved": "https://registry.npmjs.org/@defra/forms-engine-plugin/-/forms-engine-plugin-3.0.9.tgz",
-      "integrity": "sha512-RRAycdYqBwjoPqDwawIEzSab2QZjtl8wtvQPvurKGDRD2ZMbAZg44LKd3X9RKRW5eztdLs+deGgJkBPVdSVhdw==",
+      "version": "4.0.1",
+      "resolved": "https://registry.npmjs.org/@defra/forms-engine-plugin/-/forms-engine-plugin-4.0.1.tgz",
+      "integrity": "sha512-DK0NMqqXiE8Vj4g6hAPkAQ0VFZelaiR980PF8jbhhz1usFgejJH30UalItmtql429EOzNrtgQgWcFcWPT/o8Wg==",
       "hasInstallScript": true,
       "license": "SEE LICENSE IN LICENSE",
       "dependencies": {
-        "@defra/forms-model": "^3.0.559",
+        "@defra/forms-model": "^3.0.560",
         "@defra/hapi-tracing": "^1.26.0",
         "@elastic/ecs-pino-format": "^1.5.0",
         "@hapi/boom": "^10.0.1",
diff --git a/package.json b/package.json
index 1ff6c34f8..3afd0bdfd 100644
--- a/package.json
+++ b/package.json
@@ -41,7 +41,7 @@
   "license": "SEE LICENSE IN LICENSE",
   "dependencies": {
     "@aws-sdk/client-sns": "^3.911.0",
-    "@defra/forms-engine-plugin": "^3.0.9",
+    "@defra/forms-engine-plugin": "^4.0.1",
     "@defra/forms-model": "^3.0.563",
     "@defra/hapi-tracing": "^1.28.0",
     "@elastic/ecs-pino-format": "^1.5.0",
diff --git a/src/config/index.ts b/src/config/index.ts
index 554f19852..2fb2ae18b 100644
--- a/src/config/index.ts
+++ b/src/config/index.ts
@@ -287,11 +287,20 @@ export const config = convict({
     default: '',
     env: 'GOOGLE_ANALYTICS_TRACKING_ID'
   },
+
   saveAndExitExpiryDays: {
     format: Number,
     default: 28,
     env: 'SAVE_AND_EXIT_EXPIRY_IN_DAYS'
-  }
+  },
+
+  ordnanceSurveyApiKey: {
+    doc: 'The ordnance survey api key used by the postcode lookup plugin',
+    format: String,
+    nullable: true,
+    default: undefined,
+    env: 'ORDNANCE_SURVEY_API_KEY'
+  } as SchemaObj<string | undefined>
 })
 
 config.validate({ allowed: 'strict' })
diff --git a/src/server/index.ts b/src/server/index.ts
index e6ec15b07..b4006c0cb 100644
--- a/src/server/index.ts
+++ b/src/server/index.ts
@@ -165,7 +165,8 @@ export const configureEnginePlugin = async ({
       },
       controllers: {
         SummaryPageWithConfirmationEmailController
-      }
+      },
+      ordnanceSurveyApiKey: config.get('ordnanceSurveyApiKey')
     }
   }
   const routeOptions = {