Britain's borders and immigration watchdog is set to face questions from MPs over European citizenship becoming an increasingly important way for non-EU citizens to get into the country.
Chief inspector of borders John Vine will appear in front of the Home Affairs Select Committee days after his inspection of how the Home Office handles European free movement applications found that more than a third of European nationals (36%) applying to stay in the UK were born outside the region and had gained European identity before arriving in Britain.
Mr Vine also found they were often sponsoring non-European partners of their own original nationality or a similar cultural background.
Mr Vine is also likely to face questions on sham marriages after figures yesterday showed that registrars reported more than 2,000 suspicious unions last year.
Committee chairman Keith Vaz described the figure - more than double the number of reports in 2010 (934) - as "worrying".
The report released last week by Mr Vine found there was not appropriate scrutiny of suspected sham marriages.
It also found that the Home Office targeted sham marriage and trafficking by organised crime gangs, but rarely prosecuted individuals, and that caseworkers often ran out of time to interview applicants and their sponsors because applications were still being worked on as a six-month deadline approached.