Gunman behind Britain's biggest jewellery raid is jailed for 23 years

Aman Kassaye planned and executed the "high stakes" heist at Graff Diamonds in Mayfair, central London, last summer, in which 40m of gems were stolen at gunpoint.

He used a professional make-up artist to disguise his appearance and a series of getaway cars to escape across the capital, shooting at anybody who got in his way, Woolwich Crown Court heard.

Kassaye, of no fixed address, was jailed for 16 years for conspiracy to rob, a further five years for possessing a firearm and a further two years for kidnap.

Petra Ehnar, a shop assistant at the store in New Bond Street, told the jury she was "petrified" when the robbers forced her to empty the store's display cabinets with a gun to her back.

She filled a bag with 43 pieces of jewellery including earrings, necklaces and watches worth a total of 40m. One diamond necklace alone was valued at 3.5m. The gems taken in the robbery have never been recovered.

Ms Ehnar, who was forced into the street by the robbers as they made their getaway, was told she would be killed if she did not carry out their demands.

Three other men – Solomun Beyene, 25, of Marylebone, north-west London; Clinton Mogg, 43, of Bournemouth; and Thomas Thomas, 46, of Penrhyn Road, Kingston upon Thames – were each jailed for 16 years after also being convicted of conspiracy to rob.

Footage was shown to the jury of Kassaye firing a shot in the street outside the store as passers-by began to realise what was happening, sending them running for cover.

Kassaye's defence rested on his assertion that the raid was carried out "by someone remarkably like him", but he was identified by Ms Ehnar.

She told police: "This was the first time I have ever been subjected to an armed robbery and I was petrified. I was thinking, 'I am going to be shot, killed'...It is the most terrifying experience a person can be put through."

Philip Bennetts, for the prosecution, told jurors that after what happened, "his facial features would be etched in her mind forever".

Beyene's role in the heist was to buy so-called dirty telephones and hire a van to use as a blocking vehicle, while Mogg provided the London address used by the make-up artist, who did not know about the planned raid.

Thomas used the blocking vehicles after the heist, the jury was told.