iPad suddenly can’t connect to Internet

Hey-
I’ve had my iPad for a few weeks now and love it. It’s been no problem.
This morning I woke it up to check emails and got a message to say I’m not connected to the Internet.
The same happened with Safari, and any other Internet based app.
I shut it down and restarted but that didn’t help. I plugged it into iTunes and saw there was an update available so I installed it in case it helped. But still nothing.
I have a full signal strength from my wireless router.
What might be causing the problem?
Thanks.