Striking French catering workers blocked platforms and held up London-bound Eurostar trains on Monday, leaving hundreds of passengers stranded for hours at Gare du Nord station in Paris.

Departures were on hold all morning as police tried to clear the striking workers who gathered on platforms and the tracks, but by late afternoon the cross-Channel trains were running again, with an average delay of 20 minutes. Employees of SNCF, the French state railway firm, ran meal services on board as talks continued between Eurostar bosses and unions to resolve the dispute over pay and security conditions.

There was chaos at the Eurostar terminal at midday, with around 500 passengers milling about aimlessly. A commuter on the scene reported that a group of striking employees was cleared by lines of police with riot shields.

The strike was called last Friday by the French CFTC union at Momentum Services Ltd, the company which serves hot and cold meals and snacks on the Channel Tunnel trains, over a claim that its British employees are paid more than French ones.

The CFTC is also worried about what it calls "chronic staff shortages" and the security of the 50km tunnel, despite improved measures since last year's September 11 attacks. Passengers now go through airport-style checks and have their baggage scanned before boarding.

Catering staff are not considered essential crew and so a strike does not necessarily mean cancelled services - unlike train managers who forced Eurostar to cancel almost a quarter of its services for at least a day last December.

Eurostar, which marked its eighth anniversary last week, is run by the state railways of France and Belgium and a British consortium including British Airways and bus company National Express.