David Cameron has warned the eurozone's debt crisis is not even halfway through as he blamed the continent for Britain's double-dip recession.

The Prime Minister said economies struggling across the channel, which receive 40% of all UK exports, were harming the UK's prosperity.

He said: "I don't think we are anywhere near halfway through it because what's happening in the eurozone is a massive tension between the single currency that countries are finding very difficult to adapt to.

"It's going to be a very long and painful process in the eurozone as they work out do they want a single currency with a single economic policy and all the things that go with it, or are they going to have something quite different?"

The PM admitted last week's figures showing Britain's economy shrank by 0.2% in the first three months of the year - plunging the UK back into recession - were "extremely disappointing", but pledged to "strain every sinew" and "redouble all our efforts" to spark growth.

"What we absolutely mustn't do is throw away our plans for dealing with the debt, dealing with the deficit, making sure public spending is properly reduced in the appropriate areas," he told BBC1's Andrew Marr Show.

"The low interest rates we have are absolutely vital."

He said the UK was going through "a very difficult, painstaking process" of rebalancing, moving away from a focus on financial services in England's south east.

Meanwhile, shadow chancellor Ed Balls claimed Britain faced a "lost decade" of sluggish growth and high unemployment if the Government failed to change course on the economy.

Mr Balls said there was a risk of prolonged stagnation in the UK like that experienced by Japan in the 1990s.