THE armed robber who shot commuter Adam Mapleson in the chest has been sentenced to at least 12 years in prison.

But Brian Wall, 62, could spend the rest of his life behind bars after he was found guilty of shooting Mr Mapleson during a robbery on a cash-in-transit van.

Mr Mapleson was hailed a hero after stepping in to help when two security guards were held at gunpoint at Rayleigh train station, in May 2007.

Wall was handed an indeterminate sentence at Chelmsford Crown Court yesterday.

Judge Charles Gratwicke said Wall was a “wicked, callous career criminal” who carried on planning robberies even after the Rayleigh shooting.

He said: “Instead of being sickened by what you had done, you continued to play an active role in the conspiracies, sourcing cars for subsequent robberies. You are, in my judgment, a wicked, callous, career criminal.”

Wall has already spent 396 days in prison, but he will never be eligible for release unless he can show he is no longer a danger to the public.

Judge Gratwicke said: “The making of a release will be for the parole board to determine when, or if, you are no longer deemed to be a risk to the public.”

A huge operation was launched by British Transport Police following the shooting, in the early-morning rush hour on Friday, May 25, 2007.

Security guard Melanie Williamson had been carrying a cashbox containing £20,000 when she was held up at gun-point by Wall.

But IT consultant Adam Mapleson, 26, barged him to the floor. Wall then shot him at point blank range in the chest.

A jury found Wall, of Elstow Road, Dagenham, guilty of causing grievous bodily harm with intent, but cleared him of attempted murder.

Craig Rush, mitigating, said: “In respect of the allegation of the shooting of Adam Mapleson, the jury’s verdict means they found there was no intent to kill, on his part.”

Wall was also found guilty of conspiracy to commit a string of armed robberies across east London and Essex over a two-year period, and conspiracy to possess firearms in connection with these attacks.

Judge Gratwicke praised Mr Mapleson for his “bravery and courage”, and awarded him £1,000 for his actions.

He said: “This court can’t, in any way, make recompense to him for what he has suffered – that’s for other channels. But, as a mark of respect and gratitude by the community for his courage and actions, I make as high an award as I can.”

The jury in the shooting trial failed to reach a verdict on crime writer Terry Smith, 50, of Point Road, Canvey, and his brother Lenny Smith, 51, of Dagmar Road, Dagenham.

The pair were charged with conspiracy to commit armed robberies between September 2006 and April 2008, and conspiracy to possess firearms for these attacks. The retrial is expected to be held in January.