Despite police investigations into a series of scams, the Government has declined the urgings of the Advisory Board on Naturalisation and Integration (ABNI), which has been pressing for a review for the past 12 months.

The Home Office said last night it was taking time to find the right evaluation method but ABNI said the Government had not accepted its recommendation.

It can also be revealed that the Home Office has no organised record of attempts to cheat the testing system and no record of the numbers of people applying for citizenship after obtaining an accredited English language qualification – one of the two routes to citizenship or indefinite leave to remain in the country.

As previously revealed by the Yorkshire Post, a lack of regulation means, once accredited, trainers can mark the language tests themselves and there is no requisite number of hours for tuition.

As well as the language qualification, immigrants can also qualify through an online test of their knowledge of British life.

Acting ABNI chairman Patrick Wintour said its recommendation to Ministers had been "quite clear" and it would be "sensible" to have an independent review of both routes.

He said: "Our advice has been to carry out a full review and that advice has not been accepted by the Government."

ABNI was set up by the Home Office in 2004 and publicly endorsed by then citizenship and immigration Minister Des Browne to help guide the Government's plans for greater integration of would-be citizens and immigrants applying to settle in the UK.

Mr Wintour said it was generally encouraged by how the system was working but such a major public policy reform now clearly required a review.

He declined to be drawn on why the Government has not res-ponded to the advice, although it is understood the issue is seen as a "political hot potato".

Keighley MP Ann Cryer, who led the campaign for knowledge of British life and English language skills to be a prerequisite for citizenship, said she would be asking Home Office Minister Liam Byrne to set up "a review immediately or at least provide a date by when one could be undertaken in order to expose any shortcomings in the system".

Shadow immigration Minister Damian Green said: "In light of the many fiascos surrounding this issue the Government must say why they will not have a review. Otherwise people will ask what are they trying to hide."

The Yorkshire Post has previously revealed a series of scams and in the minutes to an ABNI board meeting earlier this year Mr Wintour is recorded as saying "there needed to be a body with the (necessary) teeth to address fraudulent practice".

Six people have so far been arrested in connection with a fraud involving immigrants paying up to £700 for their online "Life in the UK" test to be fraudulently passed for them at a training centre in Sheffield.

The online test has also been revealed to be vulnerable to cheating, including the widespread use of wireless technology hidden under headphones.

In Leeds about 800 immigrants were duped into paying £350 a time for a bogus English language course. West Yorkshire Police are investigating.

A Home Office spokesman said: "The UK Border Agency has not refused to carry out a review of the system for citizenship, including routes for citizenship and the related language and citizenship knowledge test."

The "most appropriate way" to carry out an evaluation was under consideration, he said.