George Osborne will step up his attack on Labour today, accusing the party of being "anti-business" and raising the spectre of communism in a speech to business leaders.

The Chancellor will warn delegates at the annual CBI dinner that Labour are in danger of breaking a political consensus that has held since the fall of the Berlin Wall — that the UK is open for business.

His comments will be viewed in the wake of Labour's tough line on the attempted takeover of British pharmaceutical company AstraZeneca by drugs giant Pfizer.

But aides to the Chancellor also pointed to Labour's rent and wages proposals and the party's plan to freeze household energy bills.

Sources close to Mr Osborne said: "It used to be jobs first, politics second, but now we have Ed Miliband going the other way."

Mr Osborne will also infuriate Mr Miliband by linking Labour to right-wing parties, which the Chancellor will say also oppose an open economy in the UK.

He will say: "For all of my adult life, since the fall of the Berlin Wall in the year I left school, there has been a political consensus in this country that Britain's future lies as an open, market economy.

"Sadly, that consensus that we put the national economic interest first, ahead of opportunist party advantage, is under threat for the first time in 25 years.

"Political parties on the left and the populist right have this in common: they want to pull up the drawbridge and shut Britain off from the world."

Labour denies that it is anti-business and argues that market controls are necessary for open economies to work and flourish.