diff --git a/shell-scripts/local-external-ipfs-node.sh b/shell-scripts/local-external-ipfs-node.sh
index cf3f13f..7be8641 100755
--- a/shell-scripts/local-external-ipfs-node.sh
+++ b/shell-scripts/local-external-ipfs-node.sh
@@ -30,4 +30,7 @@ export DBURL=mongodb://localhost:27017/ipfs-service-dev
 
 export CONSUMER_ENV=production
 
+# Lock the consumer into a preferred service provider.
+#export PREFERRED_PROVIDER=12D3KooWEzE3HNH86WCb2Xocu6PgBCnSGUD7myJmuTHvoedMwp7K
+
 npm start
diff --git a/src/controllers/rest-api/bch/controller.js b/src/controllers/rest-api/bch/controller.js
index 68eed4d..b9b03b0 100644
--- a/src/controllers/rest-api/bch/controller.js
+++ b/src/controllers/rest-api/bch/controller.js
@@ -3,6 +3,7 @@
 */
 
 const { wlogger } = require('../../../adapters/wlogger')
+const config = require('../../../../config')
 
 // let _this
 
@@ -23,10 +24,7 @@ class BchRESTControllerLib {
     }
 
     // Encapsulate dependencies
-    // this.UserModel = this.adapters.localdb.Users
-    // this.userUseCases = this.useCases.user
-
-    // _this = this
+    this.config = config
   }
 
   /**
@@ -66,6 +64,11 @@ class BchRESTControllerLib {
     try {
       const providerId = ctx.request.body.provider
 
+      // Throw an error, if the provider has been set by an environment variable.
+      if(this.config.preferredProvider) {
+        throw new Error(`Consumer has preferredProvider set in environment variable. Refusing to switch providers.`)
+      }
+
       await this.adapters.bch.selectProvider(providerId)
 
       const body = {