By Nick Assinder BBC News Online political correspondent

The firefighters' dispute was always likely to turn into a show of strength between the government and the unions.

And, as the industrial action moved into its second day and the opposition stepped up its attacks, there were clear signs that the government was hardening its stand.

Deputy Prime Minister John Prescott signalled that, if a second, eight day strike went ahead, the government was ready to order the military to cross picket lines to gain access to fire fighting equipment.

And it emerged troops were already being trained on 15 of the modern red fire engines in preparation for an escalation of the dispute.

The admission was the clearest possible sign that the government is gearing up for a difficult dispute and is ready to take on the strikers.

Prescott hardens stand

The government's hard-line stand came as the Tories seized on the strike to revive memories of the last Labour government's infamous 1979 winter of discontent.

And this is clearly a strong issue for Iain Duncan Smith, who is still attempting to get onto the front foot after weeks of sniping at his leadership.

Mixed message

He has persistently demanded to know why ministers have not attempted to get soldiers trained in using modern fire fighting equipment - suggesting they have been too concerned about crossing union picket lines.

And shadow minister David Davis has claimed that there are up to 400 reserve and training fire appliances standing idle and available for use by troops.

Ministers have not helped by sending out contradictory messages on the issue with the minister responsible, Nick Raynsford, first suggesting that allegation was true.

Later, Downing Street switched emphasis, insisting it would be technically difficult to train up the soldiers in time.

Blair is determined not to buckle

But it is clearly the case that, while negotiations were still going on, the government was eager not to make matters worse by, in effect, requisitioning equipment.

Then there is the Tory insistence that the strike breaks the 1992 trade union laws which outlaws any strike which "wilfully or maliciously endangers human life".

Political advantage

But the real danger here is that, as with all strikes, this will rapidly escalate into a purely political issue with the relative merits of the case running a bad second.

For a start there is absolutely no way Tony Blair is prepared to be seen to be caving in to strikers demands.

He believes that would badly damage his public standing while, at the same time, handing the Tories a major political advantage.

Apparently he is ready to see this one out to the bitter end, even if that means serious confrontation with the strikers - including forcibly crossing picket lines.

His determination on that is only likely to be strengthened by the opposition attacks and an escalating dispute.

The prime minister believes, with some evidence, that the public is not behind this strike and that he would be able to weather a full scale confrontation.

Closing window

It would give the Tories more ammunition - but, in his book, the alternative would be far worse.

Meanwhile, and despite what ministers may say, there are so-called "dark forces" in Downing Street who believe the FBU must be taken on and defeated.

They may not accurately represent the prime minister's view, but they are there and they are sending out their message on a regular basis.

What many fear is that there is now a rapidly closing window through which to settle this dispute.

Talks are continuing and if a compromise can be hammered out before the next strike, then face may be saved all around.

If, however, the eight day strike goes ahead then the crisis moves into an entirely different phase.

Tony Blair will almost certainly take tough action to maximise the effectiveness of troops, with all the consequences.

And that could easily escalate the strike into a bitter battle between the government and the FBU - just the one relished by the "dark forces".

And that will indeed revive memories of 1979 and even the 1984 miners' strike.