Boris Johnson wrote to Home Secretary Theresa May amid increasing concerns over lengthy lines at border control desks for those arriving at Heathrow Airport.
Passengers have complained of frustrating delays, sometimes more than an hour, because of lengthy passport and visa checks and an apparent lack of border staff.
Johnson said the delays were giving "a terrible impression of the U.K." and demanded action ahead of a busy summer in which Britain will mark Queen Elizabeth II's 60th anniversary as monarch in June, and hold the Summer Olympics beginning in July.
"This summer, with the Queen's Diamond Jubilee and the London Games, gives us a once-in-generation's opportunity to promote what is very best about London and the U.K.," Johnson wrote."It is critical for the success of these events that visitors from across the globe have a great experience from beginning to the end of their stay."
Heathrow typically handles an average of 190,000 arriving and departing passengers each day, but is braced for a major influx during the July 27-August 12 Olympics.
Johnson said that about 80 per cent of visitors and participants arriving for the Olympics will use Heathrow, which would "place short-term additional pressures on the system."
Immigration minister Damian Green confirmed some passengers at Heathrow had faced a 90-minute wait Friday to reach border desks. He said disruption had been partly caused by heavy winds and rain.
"Over the weekend there were some breaches of acceptable waiting times at Heathrow, this was caused mainly by the severe weather," Green told lawmakers.
He said Britain's border force would deploy extra staff to cope with demand, and insisted that authorities were well placed to cope with the influx of visitors during the Olympics.
"(The) border force will ensure that all immigration desks at Heathrow and other key ports ... are fully staffed at peak periods of the summer," Green said.
A contingency force of retired border staff and trained workers at other government departments will be available to step in to help ease lines if needed.
Lawmakers and Heathrow's operator BAA Ltd. had called for additional border staff to be available, mindful of the disruption experienced last summer, when Britain's then-border chief relaxed some passport checks during the busy tourist season simply to handle the demand.
May is meeting with the British Air Transport Association, the airline industry group, to discuss the recent problems.Suggest a correction