London taxi drivers are planning to demonstrate against a paranoid schizophrenic killer being allowed to study to become a black-cab driver.
The man, who cannot be identified for legal reasons, strangled his wife in 2000 and was jailed indefinitely for manslaughter in 2001.
The London Cab Drivers Club said the move jeopardised the industry, and it would be organising a protest.
Transport for London (TfL) insisted "checks and balances" were in place.
The 38-year-old man, who was detained under the Mental Health Act, was released after the parole board assessed he was no longer a risk to society, which left him free to pursue work.
A TfL spokesman said it had insisted that the convicted killer would have to undergo annual medical reports as a condition of his taking the exams.
The decision to allow him to take the exams was also being scrutinised by two independent reviewers, TfL said.
"All applicants with a previous criminal conviction are subjected to rigorous checks and we work closely with the Metropolitan Police and the wider criminal justice system before any decision is made to ensure they are suitable to be a taxi driver," said the TfL spokesman.
"In this case we received reports from all of the relevant authorities and evidence from clinicians and the decision was based on that evidence."
I believe this will affect the trust we have built up over the hundreds of years serving the London public
Grant Davis, chairman of the London Cab Drivers Club
Grant Davis, chairman of the London Cab Drivers Club, said he was in discussions to organise a demonstration.
"I believe this will affect the trust we have built up over the hundreds of years serving the London public," he said.
Bob Crow, general secretary of the RMT, said taxi drivers were "rightly appalled at this shocking news".
"This situation should never have been allowed to get this far and that's a massive failure of the procedures," he said.
A spokesman for the Sainsbury Centre for Mental Health said it could not comment on an individual case.
But he said: "The vast majority of people with an illness like schizophrenia can still work and can still lead decent, productive lives.
"Having a condition like schizophrenia - you can recover entirely from it - should not in itself preclude someone from working."
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