Other objects are preserved in water

Staff from the Museum of London say the blackened banana skin was found on a dig in former fish ponds in Southwark, and could date back to the mid-15th Century.

A spokeswoman said: "As far as we know this is the oldest banana in Britain. There is no evidence, as far as know, of bananas being brought to this country until 1633 and so it is around 200 years early."

Stephen Thurley: "The banana may have been commonplace in Tudor times"

The museum director, Simon Thurley, said the discovery has astounded archaeologists, who had thought bananas were only imported on a commercial basis in the 19th Century when refrigeration came into use.

He thought it unlikely that the fruit was a curiosity brought in as a gift to someone important because it had been thrown into a public rubbish dump.

One theory is that bananas were relatively common in Tudor England, in which case they would have been eaten when they were over-ripe since it took weeks for them to be shipped over from Africa.

Rachel Ellison reports: "At nearly five hundred years old, it's been perfectly preserved"

This might explain why there are no known references or depictions of the fruit in literature of the time.

"It may be that they have actually made references to exotic fruits - they might not have called it a banana," Mr Thurley told the BBC's World Tonight, "and it might not have looked like a banana looks today."

The banana skin has yet to be carbon-dated but since it was found on a historical site that had not been disturbed before, museum staff are sure it is not simply a piece of modern-day London litter.

Objects 'bring London to life'

The find is one of several objects uncovered from disused medieval fish tanks at London Bridge City. They include items of clothing, rare armour, tools, a bowling ball, a musical instrument like a bagpipe and the remains of a medieval boat.

"We've found a whole range of Tudor objects that suddenly bring life in London alive," said Mr Thurley.

The discoveries, which give a unique insight into Tudor London, are on display in a special underwater unit at the Museum of London until 9 July.