Unions have not ruled out strikes over pension cuts
Union leaders have not ruled out co-ordinated industrial action over cuts to public sector pensions, following talks at the TUC.
TUC General Secretary Brendan Barber said this was the issue on which the big unions were most united.
But he vowed the campaign against "deep and rapid" spending cuts would go on, with a mass protest on 26 March.
Ministers have not ruled out new laws to prevent co-ordinated strikes as a "last resort".
Cabinet Office Minister Francis Maude said any "general strike" would, in any case, be illegal.
He said the government wanted a dialogue with unions but they had to recognise that public spending had to be reduced, he added.'Huge event'
Mr Barber said: "No one is talking about a general strike, but of course these attacks on our members could well give rise to industrial action around specific disputes.
"Today's meeting showed a clear determination for unions to work together on industrial issues including, as a last resort, industrial action when members support it."
He said the government had agreed to talks with unions over the future of public sector pensions and ministers had "now accepted that they will not force through changes in the March budget".
Union leaders may talk tough over strikes but privately they know the risks are huge.
However angry their members may feel, union bosses are acutely aware that in hard times low-paid workers will be very wary of losing money by coming out on strike.
There is a fear too of the likely media and public reaction, and a recognition any campaign of industrial action could simply alienate public opinion.
The legal difficulties in calling strikes are also immense and risk playing into the government's hands by paving the way for fresh anti-union legislation.
Despite all that, the leaders of most of the big public sector unions believe they have no option if they are to show the government they are serious. To quote Mrs Thatcher, they believe "there is no alternative".
But he added: "These will be difficult negotiations as public service workers will not allow their pensions to be hammered. We hope that the talks can make progress, but we cannot rule out industrial action taking place on this issue."
He said the planned demonstration in London on 26 March - three days after Chancellor George Osborne's budget - will be "a huge event at which the British people will come together to show their opposition to the government's chosen course".
Some sources have predicted a campaign of strikes beginning in the spring - but that now appears less likely after the TUC negotiated an agreement with ministers to hold off implementing any changes until June.
Some smaller unions are calling for a more cautious strategy designed to build support among other groups, such as charities, who are affected by the cuts.'Debt legacy'
Mr Maude told the BBC that public sector workers were not to blame for the UK's budget deficit but spending did need to be cut.
"We want to engage with the unions, and we are doing so, to try and get the best result for their members," he told the BBC. "We do not want a political fight with the unions and some union leaders are sounding as if that is what they want.
"We want to engage to get the right outcome for all taxpayers that is fair for future generations so they do not have to bear these terrible costs of Gordon Brown's debt legacy."
The prospect of further industrial action has led some senior Tory figures, including Mayor of London Boris Johnson, to call for changes to trade union law to ensure that strike ballots can be lawful only if 50% of union members take part.
Mr Maude downplayed this possibility but did not rule it out.
"We think the laws work pretty well as they are and any changes to the law would be very much a last resort," he said.
The issue has risen up the political agenda following a series of high-profile strikes, including walkouts by London Underground staff and refuse collectors working for Birmingham City Council.