A Labour government would result in economic chaos with £20.7 billion of unfunded spending commitments in its first year, George Osborne said as the Tories launched an attack on the Opposition's credibility.

The Chancellor, flanked by senior Tory ministers including William Hague and Theresa May, said Treasury analysis of Labour's policy proposals revealed they would require the equivalent of an extra £1,200 of borrowing for each household.

Mr Osborne warned voters against changing course at a time when there were "warning lights flashing in the global economy".

Speaking at a Westminster press conference, Mr Osborne said: "The evidence produced today shows the Labour Party have not demonstrated the fiscal discipline or economic competence that earns an opposition the credibility to form a government.

"The evidence shows they are a risk to economic recovery.

"So the British people have a clear choice at the next election - continue on the road to a stronger economy with a competent Conservative team that have a long-term plan or choose the chaos of over £20 billion of unfunded spending promises, higher taxes and more borrowing offered by the alternatives which would take us back to the economic mess Britain was in five years ago.

"Competence or chaos. That is the choice. Let's not throw it all away, let's work through the plan."

He said a strong economy was vital to protecting public services, and announcing extra spending commitments would put that at risk.

"You cannot have a strong NHS, good schools, proper law and order without a strong economy," the Chancellor said.

"We have set out the public expenditure plan we will follow, starting with detailed, published and legislated plans for the next financial year that begins in April 2015.

"Those plans involve savings of £13.6 billion.

"What we set out today is the alternative from the Labour Party which involves £20.7 billion of spending commitments. That is equivalent to £1,200 more borrowing for every working household.

"These are spending commitments made by the Labour Party since they said they were exercising iron discipline."

The figures were costed by Treasury officials under the established Opposition costing procedure, Mr Osborne said.

Labour has insisted its plans are fully funded and have accused the Tories of failing to set out how they will pay for measures including more than £7 billion in tax cuts announced at the party's conference last year.

Mr Osborne warned voters considering backing Labour in May that it was not the time to deviate from the austerity measures he had set out.

"I say to those who would abandon our long-term economic plan: No. The plan is working.

"At 5% of GDP our deficit is down by a half, 1.75 million more people have the security of a job, 760,000 new businesses have been created.

"Last year Britain was the fastest-growing major advanced economy.

"We are on the road to a stronger economy, but we are not there yet.

"Don't put our recovery at risk at a time when there are so many warning lights flashing in the global economy.

"From the weakness in the eurozone to the instability in Russia.

"It matters now more than ever that we continue to reduce our deficit and begin to reduce our debts."

Commons leader Mr Hague warned that a Labour government would mean higher taxes and higher mortgage rates, while the Home Secretary accused the Opposition of having nearly £1 billion of unfunded commitments across the Home Office and the Ministry of Justice in 2015/16.

Culture Secretary Sajid Javid claimed Labour would "run deficits permanently, adding to debt indefinitely" and Education Secretary Nicky Morgan said the long-term future of schools would be "put at risk".

But the claims made in the A Cost Analysis Of Labour Party Policy report quickly came under intense scrutiny after it emerged that some of the analysis was based on a presumption that where Labour had criticised a government policy they would reverse it.

Mr Osborne dismissed suggestions that the document was nonsense, telling reporters: "We have been very clear that the commitments we used are ones which are either in Labour policy documents or party conferences."

"The vast majority of these commitments are ones made in very large public events by the Labour Party where clearly a lot of thought has gone into what they were talking about," he added.

Mr Osborne dismissed Labour's calls for the Office for Budget Responsibility to be allowed to audit all the major parties' election spending plans, saying an independent review had found it would "not be right at this time" to give it the extra responsibility.