A police operation has led to a gang of “untouchable” teenage armed robbers who rode on superbikes to rob banks, hospitals and newsagents being jailed for more than 50 years.

In a six-month crime spree starting in September 2010, they robbed 29 premises armed with handguns, knives and hammers twice shooting at victims, attacking another with a hammer and stabbing a shopkeeper in the arm.

The nine-strong gang who operated out of the Surrey Lane estate, Battersea, were jailed for a total of 56 years on Friday, March 2 at Kingston Crown Court.

Described as "ruthless and reckless" by police they stole hundreds of thousands of pounds during their reign of terror, committing an average of more than one robbery per week.

The teenagers used stolen motorbikes which they knew would be able to outrun police targeting 20 premises in the borough and others across south-west London including twice stealing cash in transit at Chelsea and Westminster Hospital.

Detective Inspector Tom Whorwood, from the Flying Squad, said: "This operation was about taking the negative role models out of the estates and off the streets of London.

"Also to demonstrate to them and the wider public that no one is 'untouchable' and that there are severe penalties for offences of this kind."

He said: "The breakthrough in this case came when following the one of the later offences the suspects were tracked on CCTV to a local estate in Wandsworth. "Following this officers from the Flying Squad reviewed thousands of hours of CCTV across this and other boroughs which led to the identification of other members of the group.

"The majority of the group were arrested in a series of raids on February 8, 2011.

"The main challenges were the haphazard nature of the offences and the wide choice of targets chosen by the gang from gun enabled cash-in-transit robberies to the knifepoint robberies of convenience stores which meant that predicting offences was problematic.

"The dedication and professionalism shown in achieving this is reflected in the fact that 8 out of 9 defendants pleaded guilty."

The gang attacked a branch of HSBC in Chelsea, Chelsea and Westminster Hospital and host of newsagents and mini-markets across Battersea, Tooting, Wandsworth, Fulham and Chelsea.

Ken Thackrar, owner of The Paper Shop in Chelsea Manor Street, Chelsea, said: "I was the one who was hammered. Police officers only came here four weeks ago and took a statement. It is very good to know they are now behind bars."

The owner of another business the gang robbed, who was still too traumatised to give his name, said: "They held a knife to my daughter's throat and robbed a cashbox containing thousands of pounds of cash.

"It's big relief to find out they are being locked up at long last. It happened over a year ago but we are still affected by it and the threat of more attacks means we are always on our guard."

The ringleader Sean Maher, 20, of Macey House, Surrey Lane, Battersea who was jailed for 12 years after pleading guilty to 19 robbery offences and three offences of possession of a firearm or imitation firearm.

The rest of the gang included Tyrone Attwood, 21, of Sheepcote Lane, Battersea who pleaded guilty to 11 robbery offences and three offences of possession of a firearm or imitation firearm and was jailed for 10 years.

Kieran Woods, 19, of no fixed address, admitted 12 robbery offences and was jailed for eight years.

Curtis Brown, 19, of Woodcroft Road, Thornton Heath, was found guilty of two robbery offences and one possession of a firearm or imitation firearm and was jailed for eight years.

Freddie Beasley, 19, of Totteridge House, Yelverton Road, SW11 - pleaded guilty to two robbery offences and was jailed for five and a half years.

Aaron Torre, 19, of McCarthy Court, Banbury Street, SW11 - pleaded guilty to one robbery offence and was jailed for four years.

James Gurney, 20, of Culvert Road, SW11, pleaded guilty to one robbery offence and was jailed for four years.

Rory Simmonds of Sutton - pleaded guilty to one robbery offence and was jailed for four and a half years.

Scott Leaver, aged 18, of Trott Street, SW 11, pleaded guilty to one robbery offence and was sentenced to an 18-month youth rehabilitation order.