It's mainly political
because he's a Tory and the eurofriendly Tories are a weak faction, plus he gets a few UKIP votes this way and doesn't upset the Mail. But if he wasn't, there's also financial sovereignty; the European Commission is an unelected body that would (under the original proposal) be able to enforce financial controls.
( Flapjack I spay a little mare for you, Mon 12 Dec 2011, 8:57, archived)

I heard everytime Sarkozy spoke Dave said it back to him in a silly voice.
"We have to protect the Euro."
"DURH WE AVE TO PRUTEKT THE UHRO"
( mark morrisons prison shoes I love Willie, Mon 12 Dec 2011, 9:02, archived)

He also undid his fly
and poked his finger through it. Then wiggled it every time Sarkozy started talking.
( Flapjack I spay a little mare for you, Mon 12 Dec 2011, 9:09, archived)

He made fart noises everytime Merkel started speaking.

( mark morrisons prison shoes I love Willie, Mon 12 Dec 2011, 9:10, archived)