Passengers faced chaos at Gatwick today as air traffic controllers across Europe went on strike.

Dozens of flights were cancelled and delays are expected throughout the day and tomorrow, when Spanish air traffic controllers take part in a one-day general strike.

Air traffic controllers in France stopped work from 4am to 9pm and controllers in Greece, Italy and Portugal were threatening stoppages of from one to four hours.

They are protesting at a restructuring of air traffic control across European airspace.

Today Gatwick's major carrier, British Airways, cancelled 40 flights, which included 32 to France and return trips to Pisa, Bologna, Naples, Geneva, Bilbao, Barcelona, Madrid, and Luxembourg.

A spokeswoman said: "We are advising passengers to call us before they leave home to catch their flights.

"They can re-book cancelled flights at a later date or receive flight vouchers to the value of the ticket, which can also be used for a refund."

Other airlines which have cancelled flights include EasyJet to Nice and Malaga, Air Portugal to Lisbon, My Travel to Aricife in Lanzarote, and Britannia to Palma.

Some airlines were changing routes to avoid France by flying over the sea or through Belgian and German airspace.

Delays this morning varied from two hours to around 20 hours for a flight to Greece.

Gatwick is likely to take several days to recover from the industrial action which is made worse by the Spanish strike.

A Gatwick spokeswoman said: "We are asking anyone expecting to fly from Gatwick over the next two days into mainland Europe to contact their airline to get the latest information about their flights before making their journey to the airport."

She said extra staff were working in both terminals to give information to passengers and help the ground handling agents. They were also making sure there were adequate refreshments available for delayed passengers.