AN INTERNATIONAL airport at Cliffe would risk becoming a white elephant, says Sir Richard Branson, boss of Virgin Atlantic. Urging support of his company's line in favour of Heathrow, Sir Richard's weekly newsletter to staff says: "Doing nothing is not an option."

The same words were first used by Alistair Darling, the Transport Secretary, when he unveiled the four months of consultation. Sir Richard says: "Cliffe would be a huge infrastructure project and one that risks becoming a huge white elephant.

"The cost of the airport alone is bound to exceed £10 billion. Massive additional investment in roads and railways will also be needed. And it will result in the destruction of environmentally-sensitive and internationally-renowned greenfield sites."

He says that it could only be viable if Heathrow and possibly Gatwick as well were closed. That would have a huge cost in social and cash terms. He says there are major environmental challenges that should be faced.

"Simply pricing people out of flying will not meet the Government's environmental objectives and will be detrimental to the economy," says Sir Richard. He adds that two new runways have been built in France since 1996. No full-length runway capable of taking jumbo jets has been built in the South East since the Second World War.

He warns that the pace of European airport expansion could result in companies moving to France, Germany and The Netherlands. Doing nothing would damage hotels and restaurants. He adds: "It's in our interests to ensure our views on airport expansion are heard, to safeguard our jobs and protect the aviation industry in the UK."

Virgin Atlantic says additional runways must be built in line with demand, promoting jobs, inward investment and tourism.

"The location of any new capacity must be determined by demand, and therefore must be provided at Heathrow in the first instance," says the newsletter.

Sir Richard says Virgin is disappointed the Government has excluded Gatwick and should prepare for expansion after the legal agreement ends in 2019. He is urging the Government to reopen discussions about allowing take-offs and landings on each runway at Heathrow.

Sir Richard has provided staff with prepaid postcards to send in their views to the Government.