Tories seize the day as 'New Labour coalition' collapses

For the 34 year-old Edward Timpson, the new Tory MP for Crewe and Nantwich, it was a high point in his fledgling political career that may never be bettered. For David Cameron, his boss, it was only the beginning.

A 17.6 per cent swing to the Conservatives in a northern Labour stronghold "can be the start of something different and something bigger", Mr Cameron told cheering Conservative crowds in Crewe's Market Square.

Mr Cameron said the stunning victory marked the "end of New Labour" as his party celebrated its most dramatic by-election triumph since the 1970s.

Following the Labour rout in this month's local elections, the Conservatives believe they have reached a political "tipping point" in the drive to oust Gordon Brown.

They urged caution over projections claiming Mr Cameron could win a Commons majority of more than 220 on the basis of the swing in the Cheshire seat. But they said the victory showed Labour support was collapsing in its industrial strongholds amid fury over the abolition of the 10p tax band and the rising cost of living. The Tories will step up their attempt to exploit Labour's vulnerability on the economy by portraying themselves as a tax-cutting party on the side of hard-pressed families.

Mr Cameron claimed Labour's "backward-looking and divisive" campaign in Crewe, where Mr Timpson was caricatured as a "Tory toff", had alienated voters. "I have to say, I see the men in top hats have gone," joked Mr Cameron, referring to the ill-fated attempt by Labour activists to embarrass the Tory candidate. "What is so encouraging is that thousands of people who have never voted Conservative before have come across and put their trust in the Conservative Party," he added. "What I want to show over the coming months, and whenever the general election is, is that that trust is right and that we will not let those people down." He said his aim was to build the "biggest coalition for change in our country so that we really can change the country; we really can remove this Government".

The Crewe victory – the first Tory by-election gain from Labour since 1978 – followed a massive Conservative drive for votes in the seat held by Gwyneth Dunwoody for 34 years.

With Labour support melting down and the Liberal Democrat campaign making little impact, the party was always confident of capturing the seat. But the size of the majority will raise hopes at Conservative campaign headquarters that it can capture a swathe of marginal Labour seats in north-west England at the next general election.

George Osborne, the shadow Chancellor, accused Labour of resorting to "personal class war attacks" during the campaign. "Labour under Gordon Brown has abandoned the centre ground," he told BBC Radio 4's Today. "There is a new 'nasty party' in British politics and it is the Labour Party." The Liberal Democrats put a brave face on their performance in Crewe, where their share of the vote fell from 18.6 per cent to 14.6 per cent. Nick Clegg, the party's leader, said: "This is a good result in what has been a very hard-fought contest."