Scotland Yard is under pressure to put crime artefacts including a letter from Jack the Ripper on public display.

The infamous “letter from hell” taunting police said to have been sent by the killer with half a human kidney from a victim at the height of the 1888 Whitechapel Murders is among a collection of evidence which has remained hidden from the public.

But putting them on show for three months could earn the Met Police a cool £4 million, say London Assembly members.

“It could attract 300,000 people from all over the world,” said a Tory Group spokesman.

“Scotland Yard is holding a lot of historical items which should be on public show, yet have always claimed the items are too gruesome.”

But Scotland Yard wouldn’t be drawn on the idea. A spokesman said today: “Assembly members have suggested we put on a roadshow. We haven’t responded to that idea.”

Such an exhibition would include items currently accessible only by invitation such as the Ripper letter sent with the kidney parcel to George Luske. Other items would include evidence against the Great Train Robbers.

Historical researcher Edward Stow, who has been investigating a new suspect in the Whitechapel Murders, backs the idea of a public exhibition.

He said: “London seems to be embarrassed with talking about the Ripper—but it brings tourists from all over the world and we should capitalise on it.

“Jack the Ripper is part of the fabric of London and the East End. We can look at it dispassionately because 125 years on is a fair distance of time.

“If they had been in Paris or particularly New York, they wouldn’t be ashamed of it.”

The items could be put on display when the Met moves from New Scotland Yard in 2015, it is suggested.

Assembly members are urging The Met to open its infamous ‘Black Museum’ collection to the public and use the profits for policing London.