Two men from Erith and Plumstead have been jailed for a horse-race betting fraud that netted up to £4 million and duped victims across the UK.

Police are attempting to recover money from the four men who were charged with conspiracy to commit fraud between 2010 and 2012.

Along with two others, Keith Dobson, 66, of Waterhead Close, Erith, and John Hawkins, 53, of Mountbatten Close, Plumstead, were said to have convinced people to invest in fake tipster schemes.

Dobson pleaded not guilty and was jailed for five-and-a-half years at Woolwich Crown Court and Hawkins, who pleaded guilty, was sentenced to 12 months.

David Agnew, 50, from West Sussex, and Michael Bartley, 78, from East Sussex, were also jailed for five-and-a-half years and 12 months respectively.

The men had been involved in a betting postage scam purporting high returns and guaranteed wins but victims didn't see these materialise and contacted police.

The scam worked by the team sending out glossy mailshots to people with an interest in gambling and already on betting distribution lists. The mailshots invited them to sign up for a service to receive tips on horses by calling a special telephone line in return for a fee, starting at £57.

However, once they handed over the cash, the victims found they either didn't receive the telephone number or the details supplied didn't work.

A second strand of the fraud involved scanning the cheques received for the tipster service to identify, via handwriting, potentially older people.

This was followed up by telephone calls to pick out those believed to be the most vulnerable and easily conned.

The investigation was carried out by the Met Police alongside officers from Sussex and Devon and Cornwall.

Detective Sergeant Gary Wingrove, of Bexley borough, who led the investigation from the Met, said: "This three-year investigation focussed on an organised criminal network that targeted tens of thousands of members of the public who had an interest in gambling.

"The fraud was practised in several different ways, with vulnerable elderly members of the public being specifically targeted to defraud larger sums of money.

"This was a despicable crime and we are pleased they have been brought to justice. Further investigations are ongoing to recover compensation for the victims."