By Chris Dorrell Chancellor Jeremy Hunt will likely be working late into the night as he looks to make the maths add up ahead of the Spring Budget on 6 March. One thing that has made life more difficult for the Chancellor – who is under pressure to cut taxes ahead of the next general election – is the surge in debt interest costs, which will cost the Treasury tens of billions of pounds over the next few years. The national debt is now at its highest level since the 1960s. The Bank Rate has climbed from just 0.1 per cent at the end of 2021 to a post-financial crisis high of 5.25 per cent. Altho…