Welcome to America: now stand in line for three hours. Millions of British holidaymakers and business travellers heading for the US this summer face longer waits than ever to be processed by immigration.

Research by The Independent reveals that budget cuts at US Customs and Border Protection (CBP) have sharply increased airport queues, with the worst delays in the "Sunshine State" of Florida.

The longest maximum average wait time for international arrivals at Miami airport rose last month to three hours, six minutes - a jump of almost half an hour on March. Travellers to New York JFK, and Dallas-Fort Worth risk waits exceeding two hours.

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With a record 27 million overseas visitors anticipated for the US this summer, lines are set to get even longer. In a statement from its headquarters in Washington, the CBP said: "The effects of sequestration will continue to have serious impacts on US Customs and Border Protection, including increased wait times for customs inspections at airports".

Virgin Atlantic is furious about the delays. A spokeswoman for the airline said: "At a number of US airports there are clear resourcing issues at immigration which in recent years have been getting worse, not better. We are very concerned about this and have made these concerns clear to the US authorities."

Sir Richard Branson's airline uses Terminal 4 at Kennedy airport, where delays are the longest in the New York area.

British Airways is the biggest carrier between the UK and US, and serves all seven airports with a maximum average wait over 100 minutes - including San Francisco, Houston, Washington DC and Orlando. A spokesman for BA said the airline was "in regular contact with the relevant authorities in the US in order to minimise immigration delays for our customers."

No one knows how well or badly Chicago performs, because the CBP cannot access its data for the second-busiest airport in the world.

The agency said it is hopeful that staffing issues can be tackled: "The recent passage of the Fiscal Year 2013 Appropriations bill allows CBP to mitigate to some degree the impacts on CBP's workforce".