That so little has improved since the immigration system was described as "not fit for purpose" six years ago is a glitch in the functioning of the British state that must be rectified forthwith. But the Government is going about it the wrong way.

The then Home Secretary John Reid's response to the confusion, in 2006, was to create the UK Border Agency. But yesterday's report into recent security lapses reveals a system still characterised by weak management, poor record keeping, and an alarming lack of clarity about when immigration controls can be relaxed and under whose authority.

No one comes out well in chief inspector John Vine's investigations. Managers went beyond their remit, ministers did not communicate with their officials. Blame for the chaos can be distributed throughout both the Border Agency and Home Office. And the Home Secretary's peremptory handling of the top official, Brodie Clark – who then resigned – resolved nothing.

What is clear, however, is that the lines of responsibility have become unhelpfully blurred. Given that control of a country's borders is one of the most basic functions of government, the decision to spin it out into an agency at arm's length from the Home Office was always a poor one. Even worse, it was not done well, leaving as a legacy huge organisational problems.

To call for stronger management of Britain's borders is not a matter of immigration policy, only of basic bureaucratic competence. Whatever the political decisions, there must be the ability to carry them out. The Government must reassert its grip.

Theresa May's solution is to split the agency into two separate bodies, one concerned with law enforcement and the other with border controls. She risks making the service more dislocated still. Structural change may sound bold, but it will only exacerbate the lack of co-ordination between those who set policy and those who implement it.

Changing the badges, with no extra resources, is not enough. Britain's border agency needs a root-and-branch overhaul; and it needs to be part of the Home Office.