BBC News Online explains the background to the dispute

I thought a strike was more or less a certainty?

Up until this afternoon most observers were pretty sure it was.

And there still may well be a strike in London - since workers there have voted overwhelmingly in favour of a walkout over London weighting of their wages.

But now that workers nationally have come out - albeit narrowly - against action, a country-wide strike after the legal seven-day waiting period seems off the agenda for the moment.

What was it all about, anyway?

In a word: money.

For weeks the Communications Workers Union - which has 160,000 members in the Royal Mail - has said the pay offer on the table was unreasonable and ungenerous.

The Royal Mail, struggling to get back into the black after several years of heavy losses, says it is all it can afford in the face of competition, as it will gradually lose its monopoly over postal deliveries during the coming years.

As it is, it is losing about �750,000 a day, and expectations of a wafer-thin �80m profit this year pale next to the estimated �23m daily cost of an all-out stoppage.

A wholesale restructuring is needed to stay above water, its management says, and that means changes to working practices and redundancies.

But it also says that its pay offer will give workers a 14.5% rise over 18 months - depending on implementation of the productivity changes, which include an end to second deliveries, and merging of some delivery and sorting centres.

That, says the union, is the problem.

The basic rise is just 3% in October and another 1.5% next April, with the rest carrying - as one union negotiator described it - "more strings than the philharmonic orchestra".

What happened, then? Why did the CWU members change their minds?

The union still believes the Royal Mail's position is unfair.

And it has said that a London walkout remains on the cards.

But as for its members, BBC correspondents say they believe many made a judgement call that the risk of going ahead with a strike was simply too great.

With no strike fund or strike pay available, members would have lost about �42 a day during any industrial action.

They may have feared that Royal Mail would be too weak to survive strike action, with foreign competitors in the starting blocks to take over the struggling company.

Then their jobs would have been in even greater jeopardy. This may have outweighed anger at basic pay which some postmen and women say is little more than �200 a week - and at the perks and remuneration packages given to top executives.

Without the vote in favour of action, the union's hand looks rather weaker - and management's commensurately stronger.

A letter from Allan Leighton, the Royal Mail's chairman, went to every employee ahead of the strike, saying the package on offer meant they would be "well on the way" to earning �300 a week - the amount the union has been demanding as a minimum - by Christmas.

That's it, then? The strike is off?

Don't breathe easy quite yet.

Although staff nationally voted against an all-out stoppage, it's important to remember that London workers did back action - by a margin of almost three to one.

Much of the nation's post passes through London on its way elsewhere, so if they come out on strike the ripple effects could disrupt deliveries across the country.

In any case, many experts believe the union would have held off from across-the-board national action in favour of "guerrilla" localised strikes, which a London walkout might achieve anyway.

The disruption would mean cheques failing to arrive, hurting small businesses first, and people already short on cash having to wait longer for badly-needed giro cheques.

Still, the situation for businesses and individuals in the UK is rather different now from what it was in 1996, the year the last strike hit.

Then, almost no-one had e-mail, or the ability to pay bills or make transactions over the phone or online.

Now, at least for businesses, electronic communication is routine, so the disruption may be less extreme.

And for some individuals, a few days without second class mail - most of which is credit card offers, pre-approved loan applications and other unsolicited junk - may not be entirely a bad thing.