Britain's interior minister ordered an inquiry on Saturday into the country's border force after suspending several top officials amid media reports that some passport checks were halted last summer.
The suspensions and inquiry come just months before London is due to host the 2012 Olympic Games, raising fears that criminals or militants may have been able to enter the country unchecked at a time when security was supposed to be paramount.
The Home Office (Interior Ministry) gave no explanation as to why the head of the border force Brodie Clark and some other senior staff had been suspended or why an inquiry had been initiated, but said Interior Minister Theresa May would make a statement to parliament on Monday.
Media reports said border guards were told last summer not to bother checking biometric chips on passports of some citizens from outside the EU.
Reports said this went further than a pilot scheme introduced by ministers last July that allowed checks for EU nationals to be reduced in limited circumstances, with biometric passports checked upon the discretion of the border official instead of automatically.
The opposition Labour Party blamed the relaxation on staffing cuts.
Five years ago when Labour were in power the then Interior Minister described the immigration service as not fit for purpose citing inadequate leadership.
Saturday's news could turn into an embarrassment for the Conservative Party which had campaigned on a tough immigration policy during last year's parliamentary election campaign.
After failing to win an outright majority, it formed a coalition government with the more left-wing Liberal Party.
(Reporting by Avril Ormsby; Editing by Matthew Jones)