Bosses of Britain's largest ever skunk cannabis ring have been told to pay back millions or face up to an extra seven years behind bars.

Today at Southwark Crown Court Judge Gregory Stone told the gang, who used garages and homes in Kingston, Surbiton, Epsom and Sutton, to pay back the money within six months.

Builder Terry Bowler, 43, who was living in St Albans Road, Kingston, was told to pay back £1.45m or face an extra six and a half years in prison.

He was initially sentenced to 16 years in prison in March 2010.

Mark Kinnimont, 43, who lived in a flat in Claremont Road, Surbiton, was told to pay back £1.29m or face an extra six years sentence.

Peter Moran, 40, a cousin of Mitcham and Morden MP Siobhan McDonagh, was told to pay back £1.49m or be sentenced to another six and a half years.

They had both been jailed for 14 years.

Mastermind Anthony Mills, 44, evaded capture after the gang was arrested in November 2008 but was eventually caught in Amsterdam and sentenced to 17 and a half years in prison.

He was told to pay back £1.69m or face another seven years prison sentence.

The figure was arrived at after years of investigation by financial investigators from the Metropolitan Police including identifying 12 homes in Lanzarote.

Detectives caught the gang smuggling cannabis from Holland hidden in flower boxes estimated to be around £1m a week in earnings.

The success of their operation, centring around south west London and Surrey, and their relatively clean criminal records inspired recent BBC drama The Shadow Line.

Prosecutors at the 2010 trial had found evidence of £63m criminal activity during 14 months of surveillance by Operation Karnak before arrests in November 2008.

But they admitted the figure may be the tip of the iceberg with bank accounts registered back as far as 2002.

Detectives had followed men from Worcester Park carrying holdalls stuffed with notes as they travelled to a bureau de change in East London.

They stashed money in bank accounts in Switzerland, Dubai and Pakistan.

Mills and Bowler were spotted having lunch with bank executives in Geneva.

Under the proceeds of crime act, criminals presented with a bill have to pay the money back or face up to an extra 10 years in prison without chance of early release.

As he handed down prison sentences in 2010 Judge Stone said he believed they might head abroad to Pakistan, Dubai or Switzerland to spend the millions they are believed to have hidden away.

He said: "Money of this scale doesn’t disappear into thin air."

Drugs paraphanelia and cash - including money counting machines which had processed £10.2m in six months in an attic in Poplar Road, Sutton - were seized in Surbiton, Worcester Park, West Ewell and Ashtead.

The bosses were also spotted holding a 'board meeting' in a cafe in Wimbledon.

For more see www.surreycomet.co.uk/operationkarnak