Long queues for immigration at airports risk damaging London's reputation as a top tourist city, a hotel expert has said.
The comments by Nigel Pocklington of Hotels.com came as long lines of passengers waiting to pass through immigration checks snaked back through the arrivals hall at Gatwick airport on Friday.
Recent long queues at Heathrow airport in west London have led to questions being raised about Border Force staffing levels.
Mr Pocklington said: "Continuing border delays risk damaging London's reputation as a tourist destination on the eve of the city's most exciting summer for a lifetime. Pictures of lengthy queues at passport control being beamed around the world could put travellers off from visiting the UK. This problem has to be resolved quickly and decisively in order to restore confidence."
John Longworth, director-general of the British Chambers of Commerce, described the queues as "a national embarrassment, particularly ahead of the Queen's Jubilee and this summer's Olympic Games".
He went on: "Britain has long been a top destination for global travellers, both for business and leisure. We need to be ready 24 hours a day, 365 days a year, to welcome travellers if we want to claim that our doors are open to global tourism, investment and trade.
"Business executives often tell us that one poor travel experience, a missed meeting or wasted time and money is enough to put them off doing business in a foreign market. We can imagine how images of long queues at Heathrow have affected the UK's reputation as a place to do business. With the eyes of the world on Britain this year, ministers must urgently get a grip of the situation and ensure that UK entry points are adequately staffed and working efficiently, particularly at Heathrow."
Earlier this month, airport operator BAA released figures showing that the Border Force failed to meet its targets for getting non-EU passport holders through immigration at Heathrow in April 2012.
The target at Heathrow's Terminal 5 for non-EU passengers was missed by nearly 20%. BAA also said there were immigration hold-ups of up to three hours for some passengers in April.
The Government has said the Border Force needs to change the way it operates.