Glenn Mason, 56, plundered the accounts of nine pensioners including an 83 year-old woman and a 92 year-old man living near his branch in the leafy area of Biggin Hill, Kent.
Mason, who was given an award by the Metropolitan Police in Bromley in 2009 for his crime fighting efforts, got away with the thefts for almost a year before his arrest in July 2012.
His attempts to cover up his crime by transferring money using the identity of two of his colleagues, Julie Jeffrey, 50, and James Cato, 35, led to them being sacked and charged with fraud.
It was only when Mason pleaded guilty in September that the case against them was dropped at the Old Bailey.
Andrew Lawson, representing Mason, told the court that Mason turned to gambling after his teenage son was injured by a roadside bomb while fighting with British troops in Afghanistan.
Mr Lawson said that all of the stolen money was paid into his gambling account and told the court: ‘It was late night poker and online games that are designed to tempt you into spending money in the hope of a big win.’
The court also heard statements two of Mason’s victims, Julie Amos and Leslie Pilditch, who both said they no longer felt able to trust banks.
Julie Jeffrey also described how she lost her job after her arrest and added: ‘I no longer feel proud, my life has fallen apart.’
Elaine May, the current manager of the NatWest Biggin Hill branch, also said in a statement that the thefts had ‘an ongoing impact within the community’ and put strain upon the staff.
Mason continues to live in the area with his wife and son and has been working in a local newsagents.
The judge, Mr Recorder Simon Farrell QC, told him: ‘You stole roughly £185,000 over a period of a year from nine victims who were al elderly and undoubtedly vulnerable.
‘Your fellow worker Julie Jeffrey, who was falsely arrested because you used her ID details to steal the money, described how, having worked for NatWest since the age of 16, losing her job as a 50 year-old woman and being reduced to delivery leaflets in all weathers.
‘Plainly these are very serious offences which everyone agrees cross the custody threshhold.
‘You are of previous good character and someone who has suffered considerable personal tragedy.
‘Your wife suffered from cancer in 2005 and your son at only 19 went to Afghanistan to fight for his country and was the victim of an improvised explosive device that caused him very serious injury.
‘I accept this caused you to develop a serious gambling addiction which was in fact the root cause of stealing the money from customers.
‘In my judgement I am afraid these matters are so serious that I am not able to suspend the sentence. The best I can do is to pass a sentence of 15 months imprisonment. But for your personal mitigation this sentence would have been far longer.’
Mason, of (32) Flamborough Close, Biggin Hill, pleaded guilty to a single charge of fraud.
The case against Ms Jeffrey, of Kent, and Mr Cato, of south London, was discontinued by the prosecution.
Both provided alibis when interviewed by police but they were only accepted by the Crown when Mason indicated his plea.
Mason made no comment in police interview.
