App Store Changed to US From UK

I had an email from iTunes yesterday, you know the usual weekly ones which highlight the latest and greatest of apps in the store for that week. I viewed it on my phone and clicked the links in the email only to be taken directly to the apps from the App Store. But, a moment later I realised that the App Store version had changed to US!!. I didn't do anything here. ?, I tried in vain to change it back to the UK version, only to be frustrated by a warning message each time from the App Store :- something similar to - You can only use the UK version of the App Store from this apple Id..

Solution :- I went to settings >>iTunes and App Stores >> Sign out and Signed back it. Guess what ? , My App Store popped up and said :- "changing to UK version"..

Fundamental Theory Of Troubleshooting :- Turn if off and on again..

Sigh..!?, Frustrating this..