Hundreds of victims could have fallen prey to an alleged multimillion-pound timeshare fraud run through a network of 19 companies based across the UK.

So far five people are accused of running a scam where victims were cold-called and offered a bogus paid-for service to get money they were owed from timeshare schemes.

Some were called again and told they had been defrauded, and offered another fake paid-for service to get their money back, the Serious Fraud Office (SFO) said.

Emma Luxton from the SFO said elderly and vulnerable people were among those targeted, and that this type of investment fraud is on the rise.

Investigators claim the scheme ran from January 2018 to September 2024.

In August the SFO arrested a man in his 50s as he was about to board a flight at Manchester Airport.

Fraudsters are very good at finding new ways to convince people that they are authentic and offering a genuine service

The following month four alleged accomplices – a woman in her 30s and three other men in their 50s – were also arrested on suspicion of fraud.

Ms Luxton, who is the SFO’s interim chief operating officer, said investigators need to hear from witnesses and victims who were contacted by the 19 named companies.

Those affected can fill in a questionnaire on the SFO website which will go live at 10am on Thursday.

She said: “We often find that fraudsters are very good at finding new ways to convince people that they are authentic and offering a genuine service.

“The message from us to witnesses is don’t feel ashamed or foolish.

“This could happen to anyone, this is a tried and tested method that these fraudsters have been using over a number of years.”

SFO director Nick Ephgrave said: “We will not wait for victims to be defrauded before using our specialist skills to step in.

“In September we put a stop to a suspected criminal network, and today we are calling for evidence from the public to push forward with a robust investigation.”

– The 19 companies are:

AML Executive Contracts Ltd registered in Hull
ASA Partnership Ltd registered in Manchester
DW Contract Consultancy Ltd registered in Enfield, north London
DW Law Consultancy Ltd registered in Enfield, north London
ERS Europe Ltd registered in the City of London
Harwood Advisory Group Ltd registered in Hove, East Sussex
Huntland Rock Associates Ltd (Hunter Rock Associates), registered in Yorkshire
Meta UK Group Ltd registered in the City of London
Milton Chadwick Consultants Ltd registered in Mayfair, London
The Nobel Group of Companies (including but not limited to Nobel Acquisitions and Investment Group Ltd and Nobel Business Services Ltd), registered in Leamington Spa and the City of London
Park Square Associates Ltd registered in Leeds
Rockland Associates Ltd registered in Norfolk
Silverstream Management Group Ltd registered in Fitzrovia, London
Sonata Trading Ltd registered in York
Termination Services Ltd registered in north London
The Biz Doc UK Ltd aka Business Doctor registered in Herefordshire
Timeshare Legals Ltd registered in north London
TSL Europe Ltd registered in east London
Venture Compliance Ltd registered in Leeds