Britain's public sector debt has reached $1.3 trillion - the highest amount since records began 35 years ago.

The total - equivalent to 56.6 per cent of the country's gross domestic product (GDP) - comes after the government borrowed $21bn last month, double the amount of last June, the UK's Office for National Statistics said on Tuesday.

The figures reflect dwindling tax receipts following Britain's worst economic downturn in decades as well as the cost of bank bail-outs and higher spending on social security benefits.

The $21bn figure for last month was lower than the $25.5bn forecast but also a record high for the month of June.

'Extraordinary borrowing'

Alan Clarke, UK economist at BNP Paribas, a French bank, said: "It wasn't a terrible number on the day ... but it doesn't change the bigger picture that public sector finances are in bad shape."

In the April to June period, public sector net borrowing stood at $68bn, nearly double the level in the same period a year ago.

Alistair Darling, Britain's finance minister, has forecast borrowing for the full year of $288bn, a record post-war high - but several economists say $312bn is more likely.

Mervyn King, the governor of Britain's central bank, recently said the government's borrowing levels were "extraordinary".