Planned increases in National Insurance contributions would not take place if the Conservatives win the general election, the party will announce today.

Shadow chancellor George Osborne is expected to announce that the Tories would scrap the recent 1% NI rise that Alistair Darling announced in last week's Budget.

The Tories claim that by scrapping the increase in NI tens of thousands of jobs would be protected.

Chancellor Alistair Darling announced two 0.5% increases in National Insurance to take effect in April 2011 - one in his 2008 pre-Budget report and one in 2009.