Labour has committed “electoral suicide” over the public sector strikes – handing the next election on a plate to the Tories, top national union leader Mark Serwotka said in Birmingham.

Mr Serwotka, general secretary of the 300,000-strong Public and Commercial Services Union, issued a bleak warning to Labour leader Ed Miliband that the party faced oblivion at the next poll.

The union leader, who is in the vanguard of the national battle over public sector pensions which has led to two mass national walkouts by tens of thousands of Government workers, accused Labour of “abandoning its heartlands.”

Mr Serwotka, one of the most influential union leaders in the UK, was in Birmingham to speak to public sector workers as the fight over austerity measures and job cuts continues.

He told the Post: “Labour has made a massive strategic mistake in doing what they are doing.

“It is fantastically disappointing – it almost guarantees that they will lose. We think it takes away any hope that they could have won – they are abandoning their heartlands.

“What the Labour Party has done is electoral suicide. Strategically, it makes no sense.”

Mr Serwotka’s attack follows anger at Ed Miliband’s stance on the public sector walkouts. The Labour leader initially said the strikes were “wrong” when negotiations were still under way with unions, and before Christmas was accused of hedging his bets by continuing to argue for a compromise agreement.

But the PCS leader warned that the nation faced “unadulterated misery” at the mercy of the economic markets, and said more walkouts looked inevitable, with strife for the remainder of the Parliament.

“We remain in dispute with the Government because they still want people to work longer, pay more and get less. We feel there needs to be more industrial action to stop further attacks from the Government.

“We are now reporting back to our people and we will be consulting them in the next few weeks about further industrial action. The PCS executive meets on February 9 and there will be consultation with members in February or early March. Subject to our members endorsing that, we think there will be further action.

“Our view is that people should run this country, not the economic markets, not the international speculators who are really just loan sharks. They prey on people, they prey on debt.”

Mr Serwotka said there was “no hope” if “the answer lay with the bond markets and triple A ratings.”

“We are now getting the markets choosing Prime Ministers. The markets want to make money, they do not care about the NHS.

“Our approach is that this is all upside down. We have to stop cutting and cutting, because that is just going to make things worse.

“It’s like payday loans. When you do not pay loan sharks at the end of the day, you get the bailiffs in. When a country does not pay what it owes, you get pressured to sell off your assets. Someone has got to draw a line under that.”

The PCS leader said the Government’s medicine to cut the deficit was “the wrong one” and called for the state to borrow more to encourage growth, whilst targeting the £123 billion tax avoidance bill.

“There are going to be 700,000 job cuts in the public sector. We have got four years of pay restraint. Most public sector workers in Birmingham will be 16 per cent worse off at the end of that period.

“Our argument is that the wrong people are paying the price. The right approach should be that they should grow the economy and tackle tax evasion.

“The right approach is that you invest to grow the economy. That is the way to deal with the deficit, through growth. In the short term you tackle the tax problem and you borrow more money to grow. Is austerity the way to fix the problem? – we think not.

“I see years of opposition to what they (the Government) are doing, and that will take a lot of forms.”

He attacked the proposed reforms on welfare. “We will see people out of their houses, more young people unemployed, public sector workers losing their jobs. We are talking about a generation being lost.

“People here in Birmingham will be forced to move house, their children will have to move school. The prognosis is one of unadulterated misery unless we force a change of direction.”