But a significant minority will not. The swing in Watford could be enough to send Labour's Claire Ward to Westminster. If it does, Watfordians will be able to boast that theirs is the youngest MP - Ms Ward, a trainee solicitor, is just 24. The Independent's small and entirely unscientific survey supported the party's claim that it was just ahead of the Tories, who have held the seat since 1979.
Labour needs a 7 per cent swing to overturn the 9,500 majority with which Tristan Garel-Jones won here in 1992. If the party's efforts pay off and if the win reflects a uniform national picture, Labour will have a 50- seat majority in Parliament.
Valerie Hayden, who works as a secretary in London, is typical of those unhappy Tories who will turn out in the end to support their party. "I think I've decided," she said. "Quite frankly, I can't see Tony Blair as Prime Minister. I'm not entirely happy, but I don't think anyone is entirely happy with their government. I don't want to part with our currency and I think Labour would do that."
Her concern with Europe reflects a trend in Watford that could be the undoing of the Tory candidate, Robert Gordon, who hopes to take over Mr Garel-Jones's former place in Westminster.
The Referendum Party seems to be polling strongly here - the Tories, talking down the problem, have apparently admitted that it could take 2,500 votes.
Among the former Tories who will support Labour is Edward Hain, a retired sales manager. He believes in a "Common Market", but not in a single currency or in a federal Europe. "I don't believe anybody should vote for anybody else. A month ago neither Labour, nor the Conservatives were the slightest bit interested in Europe. It's only because of the Referendum Party that they have been forced to make promises about it," he said.
Local issues are also upsetting some former Tories. Jane Seager, a mother, is angry that she has not been able to find an acceptable secondary school place for her child. She will either vote Liberal Democrat or not vote at all. "All the schools we have applied to are grant-maintained. They have been given carte blanche to do what they want by this government. I won't go blue again, but I definitely couldn't vote Labour."
Others have decided to back new Labour. Vipul Patel, director of a software company, voted Conservative in the past. This time he will vote Labour. "They've screwed it up," he said. "It's the sleaze - it's terrible. You can't vote for someone you don't trust any more."
A former Conservative-voting factory worker, who did not want to give his name, felt the same. He, too, will probably vote Labour, though he is less sure. "My money has gone up by pounds 10 in the last five years, and they voted themselves a 26 per cent rise," he said.