British Airways is to transfer a string of international services from Gatwick airport to London Heathrow.

From November, Gatwick flights to San Diego, Denver, Phoenix, Harare and Lusaka will fly out of Heathrow's terminal four.

Three Gatwick short-haul routes to St Petersburg, Tripoli and Sofia will also move to Heathrow, where they will fly from terminal one.

An extra daily flight to Athens will also be introduced at Heathrow while the daily Athens service from Gatwick will be suspended over winter.

Flights from Gatwick to the Caribbean will be increased, however, with the addition of two services a week to Antigua.

The airline's results for the last financial year were the worst since it was privatised 15 years ago.

It showed a pre-tax loss of £200 million for the year ending March 31, which included a loss of £85 million in the spring.

A spokesman for airport operator BAA said: "The announcement by British Airways is disappointing but not unexpected.

"These route transfers do not further affect planned staffing levels at Gatwick, beyond some cabin crew moves to Heathrow.

"Other airlines including easyJet are looking to expand their operation at Gatwick and only last week announced new services to Alicante and Madrid."

Airport bosses plan to spend almost £1 billion on Gatwick during the next decade despite a recent slump in profits.

They say the airport must develop to cope with an estimated 42 million passengers a year - 12 million more than at present - even though a second runway could not be built until 2019 at the earliest.

Roger Cato, managing director of BAA, which runs Gatwick, said: "It is a big sign of the confidence we have in the airport's future."

BAA will invest £80 million on segregating and improving the walkways leading to aircraft, £60 million on an extension to the South Terminal, £80 million on an extension to the North Terminal and £65 million on car park improvements.

A new mid-field satellite or mini-terminal will cost a further £250 million.