Jellybean update problem

[mblockhead]

I have an unrooted HTC One X on Icecream Sandwich (T-Mobile UK). A few weeks ago the Jellybean update was pushed OTA and I tried installing it. After downloading the update, the phone starts updating. Once the progress bar is finished, the phone comes up with a red triangle and exclamation mark obviously showing that the update hasnt work. After a minute or so, the phone boots up normally without the update and I get a notification saying the update is still available. Multiple attempts at this has the same result.

Any help would be great, thanks!