Heathrow and Gatwick airport operator BAA plans to put another £40million in to extra security but long queues over Easter and other peak times look set to continue, chief executive Stephen Nelson says.

The money will pay to recruit 1,400 extra security guards and open 22 new security lanes across airports including Heathrow and Gatwick.

Mr Nelson said the extra lanes should cut queuing to five minutes or less for 95 per cent of the time.

"As well as tackling the immediate issue of queuing times, we are ready to make major, long-term investments in British airports, that will free the traveling public from congestion and provide a good experience at our airports, all for a few extra pounds per passenger," Mr Nelson said.

But he admitted airport customer service was "unacceptable" at times and did not rule out a return to the marquees outside terminals used during heightened security alerts last year.

Heathrow chief executive Tony Douglas said that his airport had already recruited 500 security staff but acknowledged other problems at the airport, including keeping it clean, which he said posed "challenges".

"There is no question that customer service at Heathrow has been unacceptable and at times it continues to be unacceptable," Mr Douglas said.

The new Heathrow Terminal Five is due to open in a year's time.

"By 2012, we aim to have either rebuilt or redeveloped all our aging terminals and returned Heathrow to its rightful status as the world's leading international airport and a fitting gateway to London," Mr Douglas said.