UK state debt rose to levels not witnessed for more than 60 years in May despite lower-than-expected Government borrowing, according to official figures. The data, which comes only two weeks prior to the general election, underscores the financial challenge facing the next Government, with both Labour and the Conservatives pledging to cut debt. The Office for National Statistics (ONS) found that public sector net debt as a proportion to UK GDP (gross domestic product) rose to 99.8% for the month. This marks the highest reading since March 1961, the ONS said. Both Labour and the Conservative pa…