BAA has recently criticised immigration queues at Heathrow as "unacceptably" long – just weeks before the 2012 London Olympics.

The headache of potential Olympics queues has not escaped the Home Office.

One senior department source described the potential queues as "sensitive" – stressing that there will be extra resources over the Games.

"But obviously we will be monitoring the situation very carefully," they said.

"Every desk will be manned."

Privately, the Home Office is looking at how it can cope with the delays more effectively in the long-term.

Some believe delays are made worse because of travel time within airports – something that the Home Office has no control over, but passengers take into account.

And the rise of social media has made responding to delays trickier.

Joan Collins was the latest high-profile figure to take to Twitter to complain about delays.

She told her 75,000 followers: "Arrived LHR after great trip on @British_Airways but 1000s waiting at passport control – listen up Ms May – need more officers."

Whitehall faces a dilemma about rapid Twitter response.

The medium suits a conversation – but departments often require approval for tweets, meaning that many are missing a trick when it comes to rapid rebuttal.

Press officers have expressed their frustration, but Twitter engagement is unlikely to improve in the immediate future – especially for "sensitive" departments like the Home Office.

Tags: Border controls, Heathrow, Home Office, Immigration controls, Joan Collins, Olympics