By Jonathan Davies

Spending cuts will need to go on for 'years to come' in order to bring down the national debt, according to the Office for Budget Responsibility (OBR).

In it annual report, the OBR said further spending cuts, or tax rises, would be needed after this Parliament to bring national debt down. It said £20 billion worth of permanent budget cuts will be needed by 2020. If those sort of cuts are implemented, the national debt would be 40% of GDP by 2064.

If that was achieved, it would mean that it has taken the UK more than half a century to return national debt to the level it was in 2008, before the financial crisis.

The OBR said that last level, national debt stood at £1.48 trillion, 80% of GDP, compared to £600bn or 42% of GDP in 2008.

A Treasury spokesperson responded: "Our deficit is less than half what it was, but [today's] report from the OBR clearly shows the hard work that needs to be done to fix the public finances and deliver economic security and prosperity for working people."

Yesterday, the Chancellor George Osborne outlined plans to legally bind future government to maintain a surplus in the budget. But the OBR cast doubt over those plans, suggested that a UK government will still need to borrow until the mid 2030s.