Union chiefs will be warned by a cabinet minister today that a concerted programme of industrial action against the Government's austerity measures could result in anti-strike laws.
Up to one million workers are expected to walk out on 30 June in protest against the spending cuts, and further shows of union strength are planned for the autumn.
Vince Cable, the Liberal Democrat Business Secretary, will tell a union conference that such moves could backfire by playing into the hands of senior Tories pressing for fresh controls on industrial action.
Speaking at the conference of the GMB union in Brighton, he will acknowledge that "feelings are running high" in the union movement, but call for "cool heads" on all sides.
He will say: "The usual suspects will call for general strikes and widespread disruption. This will excite the usual media comments about 'a summer' or 'an autumn' of discontent. And another group of the usual suspects will exploit the situation to call for the tightening of strike law.
"We are undoubtedly entering a difficult period. Cool heads will be required all round. Despite occasional blips, I know that strike levels remain historically low, especially in the private sector. On that basis, and assuming this pattern continues, the case for changing strike law is not compelling."
But he will add: "Should the position change, and should strikes impose serious damage to our economic and social fabric, the pressure on us to act would ratchet up. That is something which both you, and certainly I, would wish to avoid."
Boris Johnson, the Mayor of London, is the most senior Tory to call for new legislation against industrial action. Speaking last year as London Underground workers staged a walk-out, he suggested that strikes should be banned unless at least 50 per cent of the union members in a workplace took part in a ballot.
David Cameron has said he believes the Thatcher government's legislation of the 1980s is adequate, although he has told MPs he is "very happy" to look at the arguments for new laws – a position that led Mr Johnson to denounce the Prime Minister as "lily-livered".
The austerity package came under pressure on a second front yesterday as more than 50 mainly left-leaning economists and academics told the Chancellor, George Osborne, that he "urgently needs to adopt a Plan B" to stop the tentative recovery from being choked off.
Ministers insisted there was no alternative to the bitter medicine being administered to tackle Britain's record budget deficit. William Hague, the Foreign Secretary, said: "It is vital to continue the course we have started."
There have been mixed signals in recent weeks over the strength of the economic recovery. Growth has been weak, business and consumer confidence are fragile, and Britain – like the rest of the industrialised world – will be hit by new signs that the US economy is struggling. The economy shrank by 0.5 per cent in the final quarter of 2010 – a fall partly blamed by ministers on the Arctic weather in November and December – before recovering by the same amount in the first three months of this year.
Some experts believe that the economy will grow by only 0.4 per cent in this quarter – well below that of France and Germany. Figures last week revealed weakness in services and manufacturing, although there was a better than expected performance by the construction industry.
Government sources said the figures underlined their warnings that Britain faced "choppy" waters as it moved out of the worst recession since the Second World War. However, they stressed that all the indicators showed growth, albeit sometimes weak.