The Conservatives have been the biggest borrowers over the last 70 years

Richard Murphy of Tax Research UK shows that Labour has borrowed less and repaid more than the Conservatives since 1979.

The Guardian was the only newspaper to pick up on this:

Research by the tax expert Richard Murphy shows that the Conservatives’ claim to be the custodians of the public finances while Labour has been the spendthrift party is unjustified. In the past 70 years, Labour governments have borrowed less than Conservative governments and repaid more debt. That holds true when adjusted for inflation and when the Conservative borrowing since 2010 (which Osborne has always blamed on his legacy from Gordon Brown) is excluded.