London's Heathrow airport is unprepared to handle the volume of travelers expected to arrive for the upcoming summer Olympics, according to a leaked government document.

Heathrow, the third-busiest airport in the world, will be overwhelmed with the volume of passengers expected this summer, with immigration wait times stretching beyond an hour and tourists forced to wait on circling aircraft or on the tarmac for blocked gates to become free.

The dire predictions, revealed by the British Daily Telegraph, come from John Whittingdale -- head of the government's Culture, Media and Sport Committee -- in a letter to Culture Secretary Jeremy Hunt.

We understand that significant preparations have been made to accommodate unusual sporting equipment, special lanes for the Olympic family, welcoming arrangements for competitors and additional Olympic ambassadors, Whittingdale writes.

However, far less thought seems to have been given to the issue of how to deal with long queues at immigration.

The UKBA (UK Border Agency) representative suggested that there was insufficient funding to ensure all passport stations would be open.

He added: While visiting tourists will understand that the Olympics is a busy time, if the wait (at immigration) is in excess of an hour it may deter tourists from returning.

The second impact may be that planes cannot unload their passengers into the terminal due to capacity being exceeded. This would lead to circling in the air, planes being left on runways or planes blocking gates.

Border Force, the agency responsible for operating border posts in the UK, rejected the claims, saying the country's airports were ready for the increase in passengers this summer.

We are well prepared for the Olympics, with additional staff available for busy periods, they said in a statement.

But we will not compromise on border security and are working with BAA to ensure that we are ready to deal with extra passengers.