Immigration remains a hot political topic

Immigration and Nationality Directorate (IND) chief Bill Jeffrey said 400 institutions had been checked after doubts emerged about their students.

Suspicions remained in 100 of the cases, he told MPs.

The figures were revealed as government officials were grilled on the recent controversy over "dodgy" visas.

Tracking fears

The Commons public accounts committee heard that checks were continuing on the suspected students.

The news comes as the Home Office prepares a register of all colleges and universities for visas checks, due to be ready by the end of the year.

Three men from south London were charged with immigration and money laundering offences after police raids to end an alleged student visa scam.

But there has been no suggestion the arrests were linked to the checks revealed on Monday.

There were mistakes made over this and it is a serious failure that we do take seriously Bill Jeffrey Immigration and Nationality Directorate

Separate government checks have also shown that 37% of people from Accra in Ghana who were granted student visas could not be traced.

Sir Michael Jay, the head civil servant at the Foreign Office, said the new register would make it easier to track people given visas.

The MPs heard there were no longer checks on people given visas leaving Britain.

Misunderstanding

Home Office Minister Beverley Hughes resigned this year amid controversy about an alleged scam over business visas issued to Romanians and Bulgarians.

The National Audit Office last week said embassy staff in the two countries estimated that they would have refused 90% of applications under the scheme but were overruled by the Home Office.

Mr Jeffrey said the Home Office had believed it could not refuse applications just because people could speak little English and offered only formulaic business plans.

But he acknowledged that an inquiry had found interpretation of the law to be misplaced.

"There were mistakes made over this and it is a serious failure that we do take seriously," he said.

Repeat 'unlikely'

Sir Michael said it was now "extremely unlikely" that such issues would continue for so long without being brought to the attention of senior managers or ministers.

He insisted morale was not low in the visa service and said the National Audit Office report was generally complimentary.

He said: "I would not accept that the system is haphazard," he argued when pressed that about why mistakes were found in 50% of visa appeal cases."