By Rory Cellan Jones BBC business and economics correspondent

But with no strikes since the end of November many people assumed the firefighters' dispute had fizzled out.

Not so - the firefighters are due to strike on Tuesday and are talking of a campaign stretching as far as May if their pay claim makes no progress.

So why has it all gone so wrong?

Future shape

The two sides started so far apart, it is no surprise that bringing them together has proved a challenge.

Andy Gilchrist faces a difficult time ahead

The union united its members behind a campaign for a 40% pay rise, the employers insisted that they could afford no more than 4%.

But the battle has moved beyond pay to a debate about the future shape of the fire service.

The government is blocking any deal that cannot be funded through higher productivity and insisting that the independent Bain review provides a route-map for the employers.

But Bain's recipe - which includes less rigid shift patterns, an end to the ban on overtime and the sharing of control-rooms with other emergency services - is seen by firefighters as an attack on jobs and on safety.

Conciliation service

The truce called by the union at the beginning of December when it agreed to enter talks at the conciliation service ACAS was not a signal that progress had been made.

The sticking point is working practices - the union is now going to have to decide just how much change it is willing to embrace in order to win more money

For the last six weeks the union has been waiting for the employers to make clear what they are prepared to offer.

What finally emerged left union leaders realising that if anything their campaign had taken them backwards.

The employers are still offering 4% at once - but only if the union signs up to the Bain agenda - and then there is the prospect of another 7% in November.

Subtle changes

Over the weekend the employers have submitted a new document with a couple of subtle changes - notably, it no longer demands that the union signs up 'unreservedly' to the Bain agenda.

It may be too late to get Tuesday's strike called off, but there is just a chance that it may be enough to get talks going again at ACAS later this week.

On pay, the two sides are no longer that far apart.

Andy Gilchrist, the FBU leader, has not mentioned 40% for some weeks.

Fraught

The sticking point is working practices - the union is now going to have to decide just how much change it is willing to embrace in order to win more money.

For Andy Gilchrist the coming weeks are fraught with danger.

He has led his members united into this battle.

Now he must show he can lead them out of it with enough gained to avoid a split in the union.