John Phillips took up to £480 a time in "accreditation fees" from applicants.
He now appears to be operating under a new guise - prompting calls for him to be arrested.
Safer Jobs, an agency which fights fraud, said it was the "biggest scam of its kind".
When his previous scam was uncovered, numerous victims told the BBC they had reported Phillips to the authorities.
But he does not appear to have been arrested, and has continued causing misery to unsuspecting job seekers, operating under the name Roy Parker instead of John Phillips.
BBC London is aware of several people who have recently lost out to the scam.
Angelique Norman paid Mr Phillips £150 and gave up a job for the promise of a non-existent position as an office assistant.
She said: "I now can't pay my rent. I'm unemployed. I can't feed my kids.
"I'm so angry with him. It's disheartening to know someone can take advantage of someone who is trying to better themselves."
She said she was "in shock" when she found out he had already been the subject of a BBC investigation.
Mr Phillips is alleged to have been carrying out the scam since at least 2012, using various names.
A former senior Met police detective has joined calls for Mr Phillips' arrest.
Peter Kirkham, now a private fraud consultant, said: "Every day he is victimising more and more people, vulnerable people, people looking for jobs.
"There are people in various levels of desperation looking for jobs because of the difficult times we live in. They need to stop him."
When the BBC confronted Mr Phillips for a second time he said: "I have nothing to say... I don't wish to talk to the BBC."
Former inspector Peter Kirkham believes Mr Phillips should have been caught by the authorities before.
"Nobody seems to have picked up that this is a linked series of offences," he said.
The Met Police said it was not aware of any investigation being carried out into the dealings of Mr Phillips.
Action Fraud said the reports of fraud were being assessed by the National Fraud Intelligence Bureau.
A conman who swindled jobseekers out of thousands of pounds as part of a recruitment scam is continuing to charge for non-existent jobs, the BBC has found.