Behind the stats: Counting the UK immigration queues

The UK Border Agency has faced widespread criticism over growing queues at Heathrow airport.

Visitors to the UK from outside the European Economic Area are not supposed to spend more than 45 minutes when waiting in the immigration queue, but over the past couple of weeks it seems that some visitors have been waiting for much longer - at least, according to some statistics.

However, Immigration Minister Damien Green has said that the situation is not as bad as some critics have said.

But with Heathrow Airport's owner BAA and the UK Border Agency publishing different data on how long people have been queuing, who should we believe?

BBC Radio 4's statistics show More or Less investigates the different ways the queues at Heathrow are being counted.

You can listen to Radio 4's More or Less on Fridays at 16:30 BST. Listen again via the Radio 4 website or by downloading the podcast.