Ministers will claim tomorrow that social mobility - people’s ability to move up the income scale and into different jobs from those of their parents - is finally improving.

Downing Street will publish research that shows social mobility has been on the up since 2000, and that young people’s chances in life are no longer as closely linked to the income of parents as they were.

The government will seize on the study, by academics at the London School of Economics and Bristol University, to counter opposition claims that Labour has presided over an entrenching of the class divide and growing income inequality, and that this is one of its biggest policy failures.

Such allegations, based on earlier research, led David Cameron to boast that the Tories were now “the party of class mobility”.

Nick Clegg, the Liberal Democrat leader, said in a speech on “social mobility in 21st-century Britain” this year that Labour had been defeated by “the opportunity gap”.

The research, assembled by the prime minister’s strategy unit at No 10, will be used as the basis for a white paper on social mobility later this year.

Brown will use this to claim that the government is preparing the country for long-term economic success after the recession.

Times Recommends

• 5 Christmas romance confessions
• Has champagne lost its sparkle?
• Your tailor-made Christmas