If militants were watching another channel, they'd know they were about to die

Among those taken hostage were embassy staff, tourists, a BBC crew and a British police constable.

In the mad rush of the storming of the embassy, the separatists made a serious oversight.

They did not realise PC Trevor Lock still had his handgun, hidden under his jumper in a holster.

For six days Lock bided his time, surrounded by militants with automatic weapons and grenades.

At all times one hostage-taker kept a finger in the pins of their grenade.

Two days into the siege militant leader Towfiq Ibrahim al-Rashidi noticed a scratching sound coming from the walls.

Lock told him it was probably mice.

In truth, listening devices were being drilled into the walls from the Ethiopian embassy next door.

Becoming aware their subterfuge efforts might be exposed, the British government instructed Heathrow Airport to direct incoming planes to fly low over the embassy.

Then, six days into the siege, the SAS pounced.

Several dozen SAS soldiers stormed the building.

As a stun grenade was dropped through the skylight, abseiling soldiers smashed through the windows.

An alert al-Rashidi was about to shoot an SAS soldier.

It was at that moment that Lock leapt forward and tackled him, saving the soldier’s life. It was only at that moment that Lock drew his firearm.

As this was going on, television crews were broadcasting the end of the siege from outside the embassy.

But the hair-raising live footage was not broadcast on ITV, which opted to continue airing Coronation Street at the time.

In the episode, Gail and Brian faced a serious cash problem. This was not to be interrupted, ITV determined.

It would later be reported that the decision to keep the soap opera on air may have saved lives.

While the lead-up to the SAS operation was being aired on the BBC, the television in the embassy was set to Coronation Street instead.

Had they not been watching the soap, the militants would have been forewarned of what was about to happen.

Five of the hostage-takers were killed when the embassy was stormed.

The sixth was sentenced to life in prison.