© Anthony Devlin/PACity of London Police and their Spanish counterparts during a raid on a suspected hub of boiler room fraud in Barcelona, Spain.
Criminal gangs blamed for fake-share scams that robbed British victims of millions of pounds in savings have been rounded up in an international crackdown involving UK police.

Officers from City of London Police joined Spanish counterparts from the Policia Nacional in a series of raids in Barcelona, Madrid, Marbella and London in one of the biggest anti-fraud operations ever staged. There were further arrests in the US and Serbia. Details are being reported for the first time after a ban on publication was lifted by a Spanish judge.

A total of 110 people were held by police on accusations of participating in boiler room fraud, where investors are duped into buying worthless or non-existent shares. Investigators targeted a number of organised crime gangs.

One of the suspects was believed to be paying £40,000 per month to rent an apartment. An Aston Martin and Ferrari were among the cars seized by police, along with various watches and £500,000 in cash.

Speaking near the site of one of the searches in Barcelona on Tuesday, City of London police Commander Steve Head, said: "What we've seen today is the culmination of a two-year investigation that has been worldwide in its nature. What we've seen is an unprecedented level of co-operation.

"We expect this network alone to have upwards of 1,000 victims. We've seen millions of pounds taken from people. "You see real victims in real communities whose lives have been devastated. Savings that they thought they could rely on in their old age have gone in a heartbeat."

The international team executed 35 warrants on offices used to run the fraud, as well as the homes of the accused.

So far 850 UK victims of the gangs had been identified, mainly pensioners, who had lost a total of around £15m, police said, adding that thousands more might have been affected.

As well as the investment scams, the gangs were involved in drug dealing, money laundering and gun crime, and use their ill-gotten profits to hire prostitutes, police said.

City of London police spent two years looking at the top levels of the fraud gangs, and aimed to take out key figures such as lawyers, money launderers and financiers. Around 40 officers from the force travelled to Spain for the operation, staged along with around 300 of their Spanish counterparts.

Most of the suspects they were targeting were British and a core group were expected to be extradited back to the UK to face trial.

It is one of the biggest ever police operations to crack down on fraud, and also involved the UK National Crime Agency, Financial Conduct Authority and Serious Fraud Office.

Of the 110 arrests there were 84 in Spain, 20 in the UK, two in the US and four in Serbia, with most of the suspects arrested on suspicion of money laundering and fraud offences.

The operation closed down 14 boiler rooms in Spain, two in the UK and one in Serbia, police said.