The group, who robbed a jewellery shop in Tunbridge Wells, also carried out reconnaissance on targets in York, Ilkley, Stratford-upon-Avon, Truro, Bath and Wolverhampton.
Ten members of the gang have now been jailed for a total of 60 years for conspiracy to rob jewellers between February and August last year.
According to the Metropolitan Police in London, the gang were stopped by the force’s Flying Squad and West Yorkshire Police as they prepared to rob Lister Horsfall in Halifax.
The group had been observed ‘casing’ the shop in the days prior to their arrest, using a house in Morley, as a base.
Police arrested six members of the gang as they prepared for the raid in the back of a white Transit van was parked in a car park in South End, Elland.
They found two mopeds, three axes, four sledgehammers, a machete and motorcycle helmets inside the van, police said today.
Two other vehicles police had been watching - a Honda CRV and a Kia Sportage - were also parked up at the venue; both were found to contain items including false number plates, motorcycle helmets and changes of clothes.
An iPad recovered from the Kia Sportage was found to contain images of Lister Horsfall and maps of Halifax, as well as web searches for various jewellers.
In the first robbery at Goldsmiths jewellers in Tunbridge Wells on February 3, three men riding two mopeds drove up outside the venue before smashing the windows with sledgehammers. They stole Rolex watches before riding away.
After that, police began to monitor the movements of the three men and discovered the group, which involved more people than initially thought, were using a network of stolen vehicles including a white Transit van and mopeds disguised with false number plates.
The group were observed as they carried out reconnaissance on potential targets in Stratford-upon-Avon, Truro, Bath, Wolverhampton, York and Ilkley. They were sentenced on Friday at Blackfriars Crown Court.
Craig Bari, 29, of Hitcham Road, Waltham Forest, London, and John Smith, 25, of Stavely Close, Islington, London eaded not guilty but were jailed for eight years after being found guilty of conspiracy to rob following a trial.
Eight other men pleaded guilty to charges in October.
Lee Jackson, 28, of Hollins House Tufnell Park Road, London, was jailed for 12 years.
Grant McCarroll, 22, of Dickson House, Drummond Way, London was jailed for eight years.
David Warren, 29, of no fixed abode, was jailed for six years and eight months.
Eugene Sheehan, 53, of Southgate Road, London, was jailed for six years and eight months.
Karim Mouzoun, 25, of Coombe House, Dalmeny Road, London, was jailed for six years and eight months.
Dane Perren, 31, of St Aubins Court, Debeauvoir Estate, London, was jailed for six years and four months.
Jamie Martin, 30, of Bowman House, Nuttall Street, London, was jailed for six years.
Jamie Freed, 44, of Southgate Road, N1 was jailed for five years and four months.
Detective Constable Richard Watson of the Met’s Flying Squad said: “This group of ten men will now spend a considerable amount of time in custody as a result of a meticulous and skilled investigation by the Flying Squad.
“Given the items found during the arrests in West Yorkshire, it is clear the group were prepared to intimidate and possible use violence to achieve their aims.
“I would like to thank the other police forces who helped us bring these men to justice and I believe this sends a strong message to those intent on committing commercial robbery that you will be pursued, arrested and put before the courts.”