Earlier this week, immigration minister Damien Green told the Commons that claims of a crisis at UK Border Control had been over exaggerated, and that it was severe weather that had caused queues of an hour and a half for non-EU nationals entering the country.
However, Walsh, speaking to the BBC this morning, has said the queue time was more like two and a half hours on Friday, using more detailed data from the airport.
He said, "Anybody who has gone through an airport in recent times has experienced the unacceptable poor standards that the border force has provided.
"The government has tried to convince people that we don't have a crisis, the government is misleading people, we have a crisis, it has been there for some time and we need urgent action.”
Mr Green accepted that queues are still too long either way, but defended his statistics, saying they are as accurate as they can be.
The Financial Times is today claiming that David Cameron has lent his support to potential plans to increase landing fees in the UK, in order to pay for more staff at the border agencies. Mr Green, however, denies discussion of such a move.