The tentacles of the mafia are spreading to the UK, as British cities become key locations in the mob's vital money-laundering operations, according to Italy's leading expert in organised crime, Francesco Forgione.

Last week Britain's Gambling Commission suspended the licence of Paradise Bet Ltd, a company based in the west London suburb of Hounslow that operates paradisebet.com. The company was shut down when its assets were frozen by Italian police as part of their operation to break up the criminal Parisi clan from the southern Puglia region, whose members are accused of attempted murder, drug smuggling and money-laundering.

Savino Parisi, the 48-year-old head of the clan, as well as politicians and businessmen, were believed to be among 74 people arrested this month by Italian officials in the city of Bari, where Paradise Bet has an operating office. Police raids in Italy, aided by Britain's Serious and Organised Crime Agency, seized 227 properties, 680 bank accounts, 61 luxury cars, nine stables, 71 horses and 35 businesses said to be worth £200m in an operation code-named "Domino".

Investigators believe that the assets seized are just the tip of an iceberg. Forgione has drawn up a list of suspected mob investments in London in which Italy's three main organised crime groups – Sicily's mafia, Calabria's 'Ndrangheta and the Neapolitan Camorra – are all represented. The 'Ndrangheta boasts a turnover of £40bn, which is larger than the GDPs of Estonia and Slovenia combined. Forgione's list starts with members of the mafia's notorious Graviano family, heads of the Brancaccio clan, who killed scores across Italy in a bombing campaign in the early 1990s.

"Members of the Secondigliano Alliance, a group of clans within the Camorra, are suspected of owning shops in London which turn out fake designer goods and also act as hideouts for fugitives and fronts for drug trafficking," said Forgione, who was president of the Italian anti-mafia parliamentary commission until 2008. He has lived under armed escort since 1995.

Forgione has the name of a London-based financial consultant who he says is linked to the 'Ndrangheta's Fazzari clan, a major force in drug smuggling. "Two suspected members of the 'Ndrangheta Aracri clan, which controls much of the Italian city of Reggio Emilia, are now based in London's West End buying up property," he added. "They are not killing in London yet, just investing."

Forgione said Italy's attempts to track down its gangsters had been boosted by the introduction in 2004 of a Europe-wide arrest warrant, since when four mobsters have been rounded up in the UK and sent home in handcuffs.

Before he was arrested in 2005, Antonio La Torre, a Camorra boss, managed to set up a small commercial empire as a money-laundering operation in Aberdeen, including an olive oil and prosciutto-importing business and a restaurant, offering jobs to Neopolitans, including Roberto Saviano, who later described his Scottish sojourn in his best-selling exposé Gomorrah.

"Thanks to the European warrant, La Torre could be arrested, but only for crimes committed back in Italy," said Forgione. "No property was seized in Aberdeen and that may still be held by the clan through front men."

The fugitive Naples gangster and alleged hit-man Gennaro Panzuto was arrested in 2007 in Garstang, Lancashire, where he was busy relaying orders back to Naples while teaching British crooks how to defraud car-leasing companies.

"The arrests of Panzuto and La Torre showed that the Camorra see the UK as a place to hide out and launder money," said the Neapolitan magistrate Michele Del Prete. "But while Panzuto has now given us names of his British accomplices, which we passed on to British authorities earlier this year, the British do not seem to be that interested."

Forgione said there was only one way of keeping Italian mobsters out of the UK. "Unless Britain and Europe introduce laws recognising the crime of Mafia membership, as we have done in Italy, and allow the seizure of assets at the moment of a mobster's arrest, the Mafia will always be one step ahead."

In his new book, Mafia Export, Forgione includes maps showing where investigators believe Italian clans have operated overseas.

In Germany, six Calabrians were gunned down on a quiet street in Duisburg in 2007, part of a long-running 'Ndrangheta feud between the Nirta and Pelle Vottari clans. This summer Germany introduced legislation to allow the seizure of assets from suspected mobsters, which Forgione described as "a start".

At the time of Panzuto's arrest in Garstang, the Naples flying squad chief, Vittorio Pisani, said he may have chosen Lancashire to avoid crossing paths with other fugitives. "It was probably not for the food or the weather," he said.