Thousands of flights have been cancelled

Members of the CGT union walked out at 0600BST, forcing the cancellation of up to 80% of French flights.

Teachers, hospital staff, postal workers and telecommunications employees were among thousands of other workers who joined the strike.

I understand the strikers - they're defending their rights. But they're taking the air passengers hostage Frederic Biagianti Stranded passenger

The Channel port of Cherbourg was blockaded by striking education workers. Nearly all roads into the town were blocked with burning barricades or human chains.

In the southern city of Marseille, bus and train drivers joined the strike, while in Paris some rubbish collectors stayed away from work for a second day.

But the impact on flights was among the most severe.

Air France said it would operate only about a third of its short- and medium-haul flights, although its long-haul flights would be less affected.

British Airways was operating only 17 of its normal total of more than 100 flights.

The French are protesting in large numbers.... but even more will attack the government if it doesn't have the courage to carry it out Francois Fillon Social Affairs Minister

"We're only running a few services today and, where possible, we will put on larger aircraft," said a BA spokeswoman.

Budget airline easyJet cancelled 50 of its 70 French services.

An easyJet spokesman said affected passengers could get a full refund or transfer to a flight on another day.

Budget airline bmibaby, which is based in the East Midlands, has cancelled all of its flights to and from France for the day.

Passengers booked on flights to Paris, Nice and Toulouse are being contacted by the airline and given alternative travel arrangements.

Dutch airline KLM said it had cancelled almost all the day's flights to and from France.

Tunnel alternative

"I understand the strikers - they're defending their rights. But they're taking the air passengers hostage," said one stranded passenger, Frederic Biagianti, marooned in Paris after flying in from the Dominican Republic.

Channel Tunnel operator Eurotunnel put on extra shuttle trains to cope with extra demand and P&O Ferries reported large numbers using its Dover to Calais vessels.

Thousands of teachers took to the streets

"This is normally a time when we carry a good number of passengers as its the school half-term holiday and we are certainly pretty busy today," a Eurotunnel spokeswoman said.

"We have increased our passenger shuttle frequency to four trains an hour."

The disruption is the latest in a string of protests by French public sector workers, angry at government plans to reform the pension system.

The bill outlining the changes is expected to be approved by the French cabinet on Wednesday, and presented to the French parliament in a few weeks' time.

The pressure on Raffarin is strong. It's up to him now to speak and to announce precise measures that are neither prevarications nor stalling tactics Patrick Gonthier UNSA education union

The proposed law would mean workers having to contribute to state funds for longer in order to qualify for a full pension. That could delay some people's retirement beyond the normal age.

Teachers, who are also angry at decentralisation plans, staged mass rallies on Tuesday in Paris, Marseille, Toulouse, Nice, Toulon, Grenoble and other cities.

"The pressure on Raffarin is strong. It's up to him now to speak and to announce precise measures that are neither prevarications nor stalling tactics," said Patrick Gonthier, secretary-general of the UNSA education union.

The government insists the pension reforms are necessary to cope with increasing demands on the pension system.

But unions have staged a string of strikes and protests against the plans.

On Sunday, hundreds of thousands of people, mainly teachers and other public sector employees, marched through central Paris.

An open-ended protest by train and Paris metro workers is due to begin on 3 June.

Keeping the peace

France's second largest union, the French Democratic Labour Confederation, has already accepted the bill.

But two other key unions, the CGT and the FO, have warned of continuing unrest if the government does not negotiate.

Social Affairs Minister Francois Fillon said: "The French are protesting in large numbers against the pensions reform, but even more will attack the government if it doesn't have the courage to carry it out."