THE strike-weary French have grown used to infrequent trains, absent teachers, undelivered post and unprinted newspapers. This is the routine whenever unions hold a one-day strike, as they are due to (again) on Tuesday October 19th, against the raising of the legal minimum retirement age from 60 to 62 years.

But the petrol shortages that have spread across the country in recent days, prompting long queues at the pump, are a different matter. A week-old strike now touches all 12 of France's refineries. With lorry drivers and school pupils also staging improvised demonstrations, France is facing a hardening of protests in what will be a crucial week in determining the fate of the pension reform.

On October 18th President Nicolas Sarkozy called ministers to a crisis meeting to work out a strategy for guaranteeing petrol supplies. France has begun to tap its industrial stocks, and fuel supplies to the main Paris airports have been resumed after a stoppage, although pilots were advised to refuel abroad where possible. Yet despite the government's insistence that there would be no petrol shortages, some 500-1,000 service stations are running low on stocks or have run dry altogether, according to the Union of Independent Petrol Importers, which supplies hypermarket stations.

Lorry drivers have joined the striking oil workers, organising slow-moving convoys that block motorways, in what is known as “operation snail”. Pupils from hundreds of lycées, too, are disrupting schools, ahead of tomorrow's strike, in which turnout is expected to be high (anything between 1.2m to 3.5m took to the streets in the previous one-day strike last week). Fewer trains are running even before the strike begins.

This week is crunch time for both sides. For those on strike, time is running out to stop the pension-reform bill going through. It has already been passed by the lower house of parliament, and the upper house is due to conclude its voting this week. Leaders of the hardline unions, including the communist-backed Confédération Générale du Travail, the country's most powerful, are under pressure from their grass-roots not to cave in. Some argue that, even if the upper house approves the bill, protests should continue; there are further legislative steps before the bill becomes law. There is precedent for such a move: in 2006, student-led protests against a proposed labour reform forced the government of the day to retreat even after it had been signed into law.

For its part, Mr Sarkozy's government is hoping to keep a lid on protests and a grip on petrol supplies until the end of the week. By then, not only should the bill be passed by the Senate, but schools will have broken up for a ten-day half-term. French unions like their holidays too much to organise strikes during the school break. Mr Sarkozy has already made some concessions on the margin, such as allowing more generous rules for women who take time out for maternity leave. But he has repeatedly said that he will not budge on the retirement age itself.

Much depends on whether organised protest turns into disorganised chaos. The petrol shortages are a worrying sign. French governments, haunted by 1968, are always nervous when students take to the streets. Though the pension reform does not touch students, it has become a touchstone for general grievances and a pretext for troublemakers to join in. Schoolchildren have been egged on by some opposition Socialist leaders, including Ségolène Royal. One pupil was hit in the eye by a police flash ball last week.There have been other sporadic clashes with police.

Should the demonstrations fizzle out by the end of the week, amid popular exasperation, the trick may well lie in finding a way for the unions to save face. Should they spin out of control, however, Mr Sarkozy could find his plans to reshuffle the government once pension reform is passed will have to be put on hold.