The Conservatives retain a comfortable lead over Labour but a hung parliament cannot be ruled out, according to two new opinion polls.

The latest Sunday Times/YouGov survey had the Tories unchanged on 40 per cent, with Labour up two points to 32 per cent and the Liberal Democrats down two points to 18 per cent. If repeated at the election on a uniform swing, the latest figures would leave David Cameron 19 seats short of an overall majority.

Meanwhile, a new ICM survey for the Sunday Telegraph also showed an eight point Conservative lead. The poll put the Tories up one to 38 per cent, with Labour down three to 30 per cent and the Liberal Democrats unchanged on 21 per cent. The survey, which follows an ICM survey for the Guardian that put the Conservatives just four points ahead of Labour, shows how the Tories have benefited from the first week of the campaign.

Elsewhere, the latest ComRes survey for the Independent on Sunday showed the Tories and Labour squeezing the Liberal Democrats. The poll put Nick Clegg's party down four points to 16 per cent, the Lib Dems' poorest performance in a ComRes poll since January. The Tories are up two points to 39 per cent, with Labour also up two to 32 per cent.

The New Statesman poll of polls now shows the Tories 15 seats short of a majority in a hung parliament.