If all the pollsters and bookmakers are right, former Tory MP Douglas Carswell is heading back to Westminster as UKIP’s first elected MP, writes Paul Geater.

But is this really the start of a political revolution – or is it just another protest by disgruntled voters?

To my eyes it looks like the latter – and I certainly wouldn’t put any money on Mr Carswell still being a member of the House of Commons in 12 months time.

I’ve been a political nerd for more than 40 years. I can remember Cyril Smith and Alan Beith being elected to parliament for the first time in the early 1970s.

And I can remember many, many extraordinary protest vote winners at by-elections that were overturned at the next general election.

Messrs Smith and Beith might have hung on to their seats – but for every MP who does make a name at a by-election there are two or three who fade back into insignificance, even if they are a big name.

Remember Bill Pitt winning Croydon North West for the Liberal-SDP Alliance in 1981? He was soundly beaten two years later.

Shirley Williams couldn’t hang on after winning Crosby a few months later.

The Tories won unlikely seats in the Midlands in the run-up to the 1979 election, and promptly lost them despite winning the big prize that year.

And of course the Tories didn’t win a single by-election between 1988 and 1997, despite winning the 1992 general election.

But isn’t it different this time? By next May Mr Carswell will have been MP for 10 years (apart from the last six weeks) and will be well known in the constituency.

I’m not so sure. When I was talking to members of the public in his constituency on the day he defected, many said they would support him.

But what struck me were the comments of two people I met: “Of course I’ll vote for Douglas in the by-election,” I was told.

“What about next May?” I asked.

“Ah, that’s different. The important thing then is to keep Miliband out. I’d like to see Douglas carry on – but if it’s a choice between the Conservatives and the Reds then . . .”

The by-election was an opportunity for people to vote with their hearts. Next May they will be voting with their heads. I’m not at all sure the result will be the same.