A siege that started after a robbery at an Italian restaurant went wrong finally ended after five days.

The 1975 Spaghetti House Siege as it became known was notable for several reasons, and is one of the cases to feature in the Crime Museum Uncovered exhibition that opens at the Museum of London tomorrow.

The Crime Museum at Scotland Yard is only accessible to the police and special guests but for the six months a selection of interesting items from it will go on public display for the first time.

Ahead of the exhibition, we are profiling some of the most infamous ever London crimes – today’s case file is the armed raid in Knightsbridge that became such a huge story.

Who was involved?

Offenders Franklin Davies, Wesley Dick and Anthony Munroe.

Where and when did it happen?

At the Spaghetti House restaurant in Knightsbridge in 1975.

What happened?

On the evening of Sunday, September 28, 1975, three armed and masked men burst into the Knightsbridge Spaghetti House, where staff had gathered to pay in the week’s takings.

The robbery went wrong and the gunmen took the staff hostage in the basement.

One man escaped and alerted the police. Firearms officers took up position in the restaurant and uniformed officers and police vehicles were positioned on the street outside as crowds gathered to watch from beyond police barriers.

The gunmen claimed they represented the Black Liberation Army and demanded safe passage to Jamaica. This was refused, but they were given a radio, coffee and cigarettes. Over the next 48 hours they released two ill hostages.

How was the case solved, what was the outcome?

As the siege progressed, journalists broadcast reports that the robbers’ demands would never be met. The Daily Mail also suppressed a story about an associate’s arrest. The police installed fibre-optic surveillance equipment in the basement and a psychiatrist advised police on the group’s mental state. On the sixth day the gunmen surrendered, releasing the hostages unharmed.

Three men were jailed for a total of 57 years.

What made it such an infamous case?

This was the first time police had used psychological strategies to end a siege. They had also enlisted the help of the media in this way for the first time and used real-time surveillance. It was the firearms wing’s first deployment in a major incident.

Which exhibits from the case will be on display at Crime Museum Uncovered?

Exhibits on display include a paper napkin with the gunmen’s demands, a balaclava and hat worn by the gunmen, a GH Daw 12-bore cut-down sporting gun carried by the gunmen, a diary written by one of the gunmen during the siege and a letter from Italian Ambassador Roberto Ducci appealing to the gunmen to let his countrymen free.

The Crime Museum Uncovered runs from October 9 to April 10. Click here for ticket information and more details