In 2010 Philip Hammond repeatedly criticised Labour's plan to increase national insurance, warning that increasing the tax rate would cost jobs and was the "stupidest tax of all".
The chancellor used Wednesday's Budget to announce he will increase the rate of national insurance for the self-employed by 2%, breaking a Conservative manifesto promise to freeze all taxes.
Hammond's team say the change is about closing loopholes and ensuring the tax system treats people equally, but the move angered opposition politicians and some Tory MPs who say the tax rise will punish workers and could hit job creation.
Footage unearthed by BuzzFeed News shows how in 2010 the future chancellor strongly criticised Labour proposals to increase national insurance rates while the Conservatives were in opposition.
"It is very clear that the increase in national insurance tax will have a negative impact on the capacity of the economy to create jobs, and I would have thought that creating jobs in the recovery would be one of the principal focuses of attention for the chief secretary and his colleagues," Hammond said in 2010, when he was the shadow Treasury secretary.
At the time Labour was proposing to increase national insurance payments by 1% for all workers, including those employed directly by companies.
Later in the debate Hammond said it was "the stupidest tax of all, on jobs" and emphasised the Conservative government would attempt to reverse any such change.
"If we win the general election, our number one priority will be to try to avoid Labour's new national insurance tax increases on the many,” he said at the time.