The jumping ship thing is perhaps a little unfair to Carswell. He does appear to be a thinking politician of conviction and has left the Tory party citing the dependency on pollsters, lack of real change, blocking of parliamentary reform and a desire to shake up the Westminster clique.
So, UKIP have their first member of parliament and No 10 have a real "Oh bugger," moment. You can hear the hurried conference call happening now, "No Prime Minister, we're not aware if the 'slippery bxstard' has been to Rotherham or not..."
Actually, if his actions rock the galloping and disconnected sense of righteous entitlement that pervades Westminster then its for the better. I wish the man well. Interesting times.