"Disturbing" flaws in security in the issuing of UK driving licences to foreign nationals have been exposed by a BBC investigation.
Secret filming has uncovered how foreign drivers who would not normally be allowed to drive in the UK have obtained licences via agents in London who illegally exploit an arrangement the UK has with Hong Kong.
The Hong Kong government and the UK Driver and Vehicle Licensing Agency (DVLA) told the BBC they were investigating.
The DVLA said work was already under way to tighten the law on standards required for drivers who exchange foreign licences.
Labour MP Louise Ellman, who chairs the Commons Transport Select Committee, is calling for an urgent review.
"This is deeply disturbing. It means there are people driving on our roads who have not passed a UK driving test that is recognised by the UK authorities," said Ms Ellman.
"That means people's lives may be at risk and it is an extremely disturbing situation - it shouldn't be allowed to happen."
Nationals from India, Pakistan, Nigeria, Malaysia, the USA, Israel and China are among those the UK government does not permit to swap their foreign licences automatically into a full UK licence without a test.
Motorists from all countries are allowed to drive in the UK for a year before being required to take a driving test if they do not qualify for an immediate swap of their foreign licence.
An investigation for BBC London's Inside Out programme revealed agents in the capital are arranging to swap foreign licences into UK ones via a Hong Kong licence, which the UK does accept automatically, to bypass the rules.
The BBC tracked down the original applications and found fraudulent details used as proof of address in Hong Kong and fake addresses scrawled on envelopes.
Hong Kong based lawyer Raymond Tse, who is experienced in civil, criminal litigation and transport issues, said: "My reaction is that the Hong Kong transport department has been used or manipulated.
"If the driving licence in Hong Kong, which is not an identity, can be converted to such an important identity document in the UK then that makes me very worried."
An Indian researcher for the BBC, who was not able to drive here, handed over his passport and Indian driving licence to one of the agents in Edgware, North London.
Within several weeks, he had received a full UK licence from the DVLA that had originated from a fraudulent Hong Kong licence.
Since 2010, nearly 13,000 Hong Kong licences have been swapped for UK ones under a special exchange arrangement.
This represents the second highest number of UK driving licence swaps from any country in the world.
The DVLA said it was not clear how many driving licences had been affected as it did not keep records of where the drivers of Hong Kong licences, swapped into British ones, originally came from.
The UK driving licence has taken on more importance as an identity document and in addition to driving, can be used to take a domestic flight, open a bank account, prove age or gain credit.
"It's very alarming, I'm stunned," said Prof Richard Aldrich, who has previously advised the UK government on international security.
"It's extraordinary that people can obtain a real driving licence via these unorthodox means. It's very troubling.
"It's almost certain some of these documents are being used for dubious purposes.
"We're talking people trafficking, drug trafficking and at the top of the list is terrorism.
"We recall the people who perpetrated 9/11 also had dubious driving licences."
A Hong Kong government spokesperson told the BBC: "We will conduct an investigation into alleged abuse cases.
"Depending on circumstances, these cases may also be referred to the police for consideration of appropriate enforcement action."
Asked whether the DVLA was doing enough to check licences, its director of corporate affairs Hugh Evans said: "We exchange some 30,000 licences in the UK each year and in all we've got some 44 million driver records and have some eight million licences issued annually.
"The DVLA does check licences, we work closely with the police."
The BBC will be handing over its evidence exposing the illegal trade in UK driving licences to the authorities in the UK and Hong Kong.
BBC One viewers in London can watch the full report on this investigation on Inside Out on Monday at 19:30 GMT.