An armed policeman who shot the Fishmongers’ Hall terror attacker in the head after his bloody atrocity has told an inquest: “I saw his bomb belt and thought we were all going to die.”

The officer, who can only be known as WS5 to protect his identity, told an inquest jury he remembered coming face to face with homegrown jihadi Usman Khan as bystanders pinned the armed killer to the ground on London Bridge.

It was then that the officer saw an improvised explosive device (IED) wrapped around Khan’s waist, and feared the worst.

Giving evidence on Thursday, WS5 said: “I got myself involved, started to pull people off and noticed an IED on Khan on the floor.

Incident at London Bridge
Usman Khan at Bank station on his way to attend a prisoner rehabilitation event at Fishmongers’ Hall in London where he killed two people (Metropolitan Police/PA)

“If you’d seen films you would have believed it was a viable device – various packages of cigarette packet size, tape, wires coming out.

“To me, it looked viable and real.”

He added: “If I’m honest, I didn’t think I was going home.”

He added: “When I was in his face, in his personal space, I remember him shouting ‘Allahu Akbar’ (meaning ‘God is great’) at me.

“At that point I thought ‘That’s it, I’m not going home to see my family or my friends either’.”

WS5 pulled bystander Darryn Frost off Khan before two colleagues fired a Taser and two shots, striking the suspect as the 28-year-old tried to get up.

Khan then remained prone on the ground for roughly the next eight minutes before he began to sit up, at which point WS5 and colleagues opened fire.

WS5 said: “I remember in disbelief he kind of sat up, which threw me and us all, how he’s still moving around and sitting up.”

It was at this point that WS5 opened fire.

He said: “I remember taking various shots.

Incident on London Bridge
Communications manager Darryn Frost carrying a narwhal tusk which he used to try to disarm Usman Khan on London Bridge (Metropolitan Police/PA)

“I looked through my sight, it went to his forehead.

“He (Khan) put his hand to his head in disbelief and so I went for central body mass.”

In all, six officers fired 20 shots during a 10-minute period, although there was a lengthy gap between the first two shots and the remaining 18.

Khan was pronounced dead around an hour later, once the scene had been made safe.

The IED was later found to be a fake.

Asked by Fiona Barton QC, for City of London Police, whether he thought the device was capable of causing an explosion and a threat to life, WS5 replied: “I believed it to be a viable device and if I hadn’t neutralised it at the time I believed we would all be dead.”

Khan stabbed Cambridge graduates Jack Merritt, 25, and Saskia Jones, 23, to death at a prisoner education event at Fishmongers’ Hall on November 29 2019, having been released from jail nearly a year earlier after serving eight years for plotting a jihadi training camp in Pakistan.

The inquest, at the Guildhall in the City of London, continues.