Brown prepares to fire starting gun for General Election campaign

After a long period of anticipation, Mr Brown is expected to visit the Queen later today to request the dissolution of Parliament ahead of an election on Thursday, May 6.

The month-long campaign promises to be the hardest fought for many years, with Labour and the Tories closer in the polls than at any election since 1992.

Yesterday's Bank Holiday was dominated by pre-election skirmishes between the parties, as Mr Brown and Chancellor Alistair Darling attacked Tory tax-cutting plans, while Shadow Chancellor George Osborne unveiled a new Tory poster accusing Labour of crushing the recovery.

Meanwhile Labour has enjoyed a surge of support in the past week and is now just four points behind the Conservative Party, according to a poll last night.

The ICM survey for The Guardian suggests that the Tories have yet to establish a firm lead and that Labour could even emerge from the General Election with the most MPs.

It puts Labour up four on 33 per cent since last week, and the Tories down one on 37 per cent. The Liberal Democrats are down two on 21 per cent.

But a further poll last night gave the Tories a commanding 10-point lead – the kind of margin they need for a Commons majority. The Opinium survey for the Daily Express put the Tories on 39 per cent and Labour on 29 per cent, both up one point on last week.

The Liberal Democrats were on 17 per cent, down one.