Sharon Allcock gets a close up of the medical instruments up for sale

The reason the mould has made its way to Christie's in London is that it was used by Sir Alexander Fleming in his ground breaking work discovering and developing penicillin.

It was snapped up by a dealer from Cheltenham on behalf of an American client for £8,050.

Important souvenir

The mould was part of a major sale of medical instruments at the world renowned auction house.

Penicillin has saved thousands of lives

It is signed on the underside "the mould that makes penicillin, Alexander Fleming, 1954", and was written a year before Fleming's death in London.

Penicillin was discovered by Fleming in 1929 and was ready for commercial use by 1940. Fleming and two colleagues went on to share the Nobel Prize for Medicine in 1945.

Lucky discovery

The discovery of penicillin came when Fleming, who also won a knighthood for his discovery, forgot about a sample of bacteria he had left under a microscope in his lab at St Mary's Hospital in Paddington, London.

When he later stumbled across the bacteria he was surprised to see that a substance called penicillium had greatly reduced the spread of the bacteria, giving birth to penicillin and the antibiotic range of drugs.

Without penicillin many illnesses would remain incurable and life expectancy would be years lower.

First guinea pig

Penicillin was first used in the 1940s

After successful tests on animals, the first human guinea pig for penicillin was a policeman called Albert Alexander, who was dying of streptococci, a lethal festering infection.

Despite improving his symptoms, an inability to produce enough penicillin meant he later died.

Penicillin was first produced on a large scale during World War Two, when millions of soldiers benefited.

Last year about 14,000 tonnes of penicillin was produced, worth £200m.

In total the auction raised £7,500. Items includeds domestic medicine chests, pharmaceutical accessories, hearing aids and surgical instruments.