Sean Lynch lived in a £1 million house on a private gated estate in Surrey. Ricky Johnson led an itinerant lifestyle on caravan parks in Gloucestershire and Worcestershire.

Both were career criminals earning large amounts of money by breaking the law and both were jailed this week.

Lynch, 46, was sentenced to 18 years for his role in running a drugs gang dealing in Class A, B and C drugs - cocaine, amphetamines and cannabis.

Drugs with a street value of £600,000 were seized when police raided a terrace house in Tooting, southwest London, where Lynch was a regular visitor.

Almost all the cocaine was found packaged in pellets that had been swallowed and smuggled into the country by human drug “mules”.

Knuckledusters and flick knives were found at the house in Tooting and in the master bedroom at Lynch’s home, a large detached house in Warlingham, Surrey.

That property has been seized under the Proceeds of Crime Act along with Lynch’s collection of cars and vehicles. These included a Rolls-Royce, a £170,000 Aston Martin, a Ferrari, a Mercedes convertible, a BMW and a Range Rover. He also owned an American police motorcycle and a liveried American police patrol car.

“Lynch was clearly the leader of the gang,” said Detective Inspector Pete Fulton, of Surrey Police.

“A financial investigation could not identify any visible form of legitimate income or investments sufficient to maintain such a lifestyle.”

Jailing Lynch at Kingston Crown Court on Wednesday, Judge John Crocker, told him: “I am quite sure you were the organiser, the man who kept very much in the background.”

Two other members of Lynch’s gang, Stephen Voller, 56, and David Warwick, 34, were jailed for 14 and 12 years respectively. A confiscation hearing to decide if Lynch will be stripped of his assets permanently will be held in December.

Compared with Lynch’s drug trafficking, the criminal activity of the Johnson gang looks more like old-fashioned villainy.

However, the family firm, which had been involved in crime for 20 years, put a large amount of time into planning and executing some of the most audacious domestic robberies in Britain. Some art experts have estimated the value of the items stolen by the Johnsons – Ricky, his sons Chad and Albi and two other relatives – at £80 million.

At Ramsbury Manor, Wiltshire, the home of the property developer Harry Hyams, they made off with art and antiques valued at £23 million, including furniture, porcelain and clocks. Mr Hyams fell 49 places in The Sunday Times Rich List after the burglary.

The Johnsons also had extensive contacts, including crooked dealers in the art world, who were prepared to buy the proceeds of their raids and spirit them out of Britain to overseas collectors.

Despite its members appearing in court regularly, the gypsy gang was not cracked until five police forces combined to form a special task force.

Charles Dupplin, an art expert at the specialist insurer Hiscox, said: “A case like this is incredibly rare. The Johnsons are a very hardened bunch and were well organised and seemed utterly disregarding of the law.”

The likes of Lynch and Johnson pale in comparison, however, with men such as Terry Adams, whose organisation dominated the London underworld for years. Adams, now in prison, was an avid consumer of stolen art and antiques. When police raided his home in Mill Hill, North London, in 2003 they found a collection of etchings, furniture and vases.

Adams was jailed for seven years in March 2007 after pleading guilty to laundering £1 million of his multimillion-pound criminal fortune. He and his brothers Tommy and Patsy ran a criminal empire based on loan sharking, protection rackets and money laundering in the Hatton Garden gem district of Central London. Adams was convicted after a 21-month investigation during which listening devices were planted in his home.

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