A bungling master of disguise has been jailed for 14 years for carrying out a string of "calculated and frightening" armed robberies.

Henley Stephenson, 41, terrorised members of the public with a semi-automatic pistol during the robberies, which date back more than a decade.

The gun-toting thug completely altered his features by concealing his black skin with the lifelike latex mask during some of the raids. With his identity hidden in the white mask, he pounced on a
cash-in-transit security guard outside a Tesco Express store in Harrow, north London.

CCTV images show him sporting an orange high visibility jacket and a pair of dark glasses to complete his look. He made off with about £250 in cash.

In further robberies, customers were sent running for cover as he stormed into stores with two accomplices, once firing a weapon into the air in a betting shop.

The gang of three was finally arrested after they targeted another security guard outside a branch of Currys in July. The group lay in wait in a blue Vauxhall Zafira with false number
plates before Stephenson, armed with a semi-automatic pistol, grabbed the box containing £19,800.

They were held by police who swooped moments later as they tried to flee the scene in Staples Corner, north London.

Detectives linked the crime to another four offences using evidence gathered from CCTV, mobile phones, witness statements and surveillance operations.

Stephenson initially pleaded guilty to five charges against him.

He later admitted a further 14 historic robberies across north London dating as far back as 1999.

Detective chief inspector Harry Hennigan said: "Stephenson executed these crimes in a calculated and frightening manner with no regard for innocent members of the public.

"His measures were so extreme, he tried to deceive the police by concealing his identity by wearing a lifelike latex mask which completely altered his skin colour and appearance."

Stephenson, of Westminster, central London, was handed the 14-year prison term at Wood Green Crown Court for 19 counts of robbery and five counts of possessing a firearm, officials said.

He will serve half his sentence behind bars, minus the 310 days he has already spent in custody.