As many as half-a-million people entered the UK through Kent without being checked against a list of suspected terrorists and criminals, it has been revealed.

Vital security checks against the Home Office Warnings Index - a database of people banned from entering the country - were not completed on around 500,000 Eurostar passengers since 2007.

The same checks were suspended at Calais and Coquelles more than 130 times. On one occasion, they were relaxed for more than six hours.

The figures were revealed as the Home Secretary said the UK Border Agency needs a "whole new management culture".

Theresa May addressed parliament following a report published today into the relaxation of security.

The investigation was carried out by John Vine, the independent chief inspector of the UK Border Agency .

He found Eurostar passengers from within the EU who travelled to the UK on trains from Disneyland Paris and seasonal services from Avignon and Bourg-Saint-Maurice were not routinely checked.

Only those fitting a "targeted profile" and passengers from outside the EU were checked against the Warnings Index. Mr Vine said that was of "considerable concern".

The checks at Calais and Coquelles - immigration checks are carried out before passengers arrive in the UK - were suspended to prevent emergencies, overcrowding or to ease congestion on roads leading to the ports.

Mr Vine said there was "a lack of effective management oversight of the frequency with which checks had been suspended, the reasons for this and which ports were suspending checks".

"Had this been in place, it would have enabled the UK Border Agency to reduce the number of suspensions of these important checks," he added.

In Ms May's speech to MPs yesterday, she said there needs to be a new set of guidelines for border control, detailing the minimum level of mandatory checks.

She announced the UK Border Force will be split from the Border Agency and become accountable to ministers.

She also said that UK border controls have been inconsistently policed for at least the last five years, adding that border staff went "over and beyond" any scheme approved by ministers to relax checks.