pbr The Tories will unveil their manifesto later as the latest polls suggest their lead over Labour is holding up.br ppbr ICM puts the Conservatives on 37 per cent, unchanged from a week ago, Opinium Research puts them on 39 per cent, also unchanged from last week.br ppbr However, while ICM shows support for Labour falling two points to 31 per cent, Opinium puts them two points up on 31 per cent. ICM shows the Liberal Democrats down one point on 20 per cent while Opinium has them unchanged on 17 per cent.br ppbr A ComRes poll put the Tories on 37 per cent, down two points since last week, Labour down two on 30 per cent and the Liberal Democrats up four on 20 per cent.br ppbr It comes as David Cameron prepares to unveil a policy blueprint that he says will "show how we are going to be different and how we are going to make a difference".br ppbr Labour's manifesto, announced on Monday, puts the economic recovery, the NHS and schools at the centre of their campaign. The Conservative leader dismissed it as "nothing new".