GUARDING Britain's borders has always ranked high on the Conservative Party's priority list.

So when it emerges that hundreds of thousands of people were let into the UK last year without full checks, any Tory Home Secretary is obliged to put the subject at the very top of her list entitled "Something must be done".

Yesterday it emerged that the thing to be done is the splitting into two of the UK Border Agency (UKBA), in which, starting next week, the Border Force will become a separate entity with its own distinctive ethos, based on strict law enforcement.

This follows a report by John Vine, the independent chief inspector of UKBA, which concluded that security checks had been suspended regularly and enforced inconsistently since at least 2007. This included failing to check half a million Eurostar passengers against the Warnings Index, a Home Office list of people of concern, such as known criminals or suspected terrorists. The report does not get drawn into the "He said/she said" row between former head of the Border Force, Brodie Clark, and Home Secretary Theresa May. She claimed that he overstepped his authority by relaxing time-consuming checks on everyone, including low-risk passengers. He says Mrs May conflated two things: a pilot scheme that allowed for certain checks to be relaxed and a general understanding that when queues at immigration were so long as to present a danger, checks could be abbreviated on grounds of "health and safety". This practice pre-dated the introduction of technology to check fingerprints.

Labour and the unions have suggested that staff shortages and the prospect of more imminent cuts at UKBA were behind these decisions. They claim officials were under pressure to keep queues down at busy times.

If that is the case, it is difficult to see how hiving off the Border Force into a separate body is going to help. It may even offer scope for mutual recrimination between the Border Force and other UKBA staff.

The irony of this story is that the pilot project, which focused resources on high-risk passengers, seems to have been a success. There was a 10% rise in the number of illegal entrants detected and a big rise in the seizure of Class A drugs. But, having crossed swords with Mr Clark, Mrs May may have felt obliged to make major changes.

As the new Border Force is being brought back under the direct control of the Home Office, there is no-one else to blame the next time something goes wrong.