SHADOW Chancellor Ed Balls has accused George Osborne of failing on the self-imposed tests of his economic policies after rating agency Standard & Poor's (S&P) put the UK on negative watch.

The Labour MP said the announcement, following similar moves earlier this year by Fitch and Moody's, which both revised the UK to a negative outlook, had left the country facing an unprecedented situation.

It came after the Chancellor said in his Autumn Statement last week he would not be able to start bringing down national debt as a percentage of gross domestic product in 2015/16.

Britain's triple AAA status came under pressure after S&P said there was a one in three chance it could lower the rating within two years, if economic conditions weaken.

The agency said it expected Government debt as a percentage of GDP to continue to rise in 2015, before declining again, with future employment or growth shocks putting more pressure on finances.

Mr Balls said: "George Osborne is now failing on all the tests he set for his economic policies. We have the unprecedented situation of all three main credit rating agencies putting Britain on negative outlook. Standard & Poor's is clear that weak economic growth has led to their estimates for the deficit and debt being revised up.

"We have always warned the Government not to set their economic policies by what the credit rating agencies say, but George Osborne has repeatedly set their views as the key benchmark of success or failure. And he is now failing on the tests he set himself."

The agency said: "Many of the factors that have restrained growth in recent years will likely continue to do so in the near term."

A Treasury spokesman said the move brought S&P in line with rival agencies.