Liam Newman, 31, was sentenced for his involvement in two of the robberies – at Mr G Mini Market in Sompting on August 13, 2016, and Ladbrokes in Rowlands Road, Worthing, on August 18.
He had pleaded guilty to two counts of robbery and two counts of possession of a firearm or imitation firearm.
Prosecutor Nicholas Hall told Lewes Crown Court this afternoon: “Mr G Mini Market was being looked after by a female assistant.
“When he noticed the assistant coming onto the shop floor he pointed a handgun at her and demamded that she open the till.
“He grabbed as much as he thought he could get away with.
“He told the assistant to get a bag and fill it with cigarettes.”
Newman, of no fixed address, then made his escape with a haul of £800 cash and £165 worth of cigarettes.
Mr Hall added: “Fortunately, the shop had CCTV showing part of a distinctive tattoo on one of his wrists.”
The prosecutor then told the court how Newman waited outside during the second robbery at Ladbrokes betting shop while a Damien Gilbert, 24, of no fixed address, went inside.
Mr Hall told the court: “He stormed into the shop screaming ‘this is a robbery!’.
“He was holding what appeared to be a handgun and pointed it at the shop assistant.”
Gilbert got away with cash and met Newman outside where they were driven away by a woman in a getaway car, Mr Hall added.
According to the prosecution, a witness said Newman was seen to be ‘hanging about’ and ‘encouraging Gilbert to get on with what’s going to happen’.
The firearm used in the robberies has never been found, the court heard.
Gerry Mohabir, defending Newman, said he was ‘very troubled’ and had a ‘very difficult childhood’.
He also told the court Newman suffered from personality disorders.
He added: “Mr Newman has had nothing short of a tragic family history.”
Discussing Newman’s long history of criminal offences, Mr Mohabir argued most of his previous criminal convictions had been against those he knew, rather than against members of the public.
He also addressed Newman’s drug problems: “It is perhaps somewhat of an irony that it was at HMP Lewes that he started using heroin, which was his downfall.”
Mr Mohabir said Newman had also used the drug ‘spice’ which he added ‘is a blight on the community at the moment.’
Sentencing Newman, judge Jeremy Gold said: “You have pleaded guilty to serious robberies.
“In the first of these you entered and threatened the female assistant with a handgun.
“In the second, you were outside the betting shop effectively as lookout.
“It is important that you understand that this is terrifying for people who are the subject of these robberies.”
Judge Gold said he believed Newman posed a ‘significant risk of serious harm to the public’, but agreed he should have credit for his guilty plea.
He added: “Sadly, you react to unhappy events in your life by excessive drug use and criminal offences.”
Newman was jailed for a total of nine years, with an additional five years to be spent on licence after his release.
Gilbert will be sentenced for one charge of robbery and one charge of possession of a firearm or imitation firearm for the offence at Ladbrokes tomorrow.
Neither Newman nor Gilbert were charged with any of the other linked robberies.
Speaking after the sentencing, Detective Sergeant Jason Vickers said: “We are happy with what the sentence is today.
“Because of the serious nature of it there is such a high sentence.”
DS Vickers praised the ‘fantastic’ support of victims and witnesses throughout the investigation, which allowed police to assemble an ‘overwhelming’ case of evidence.