DURING the past 300 years it has been a health retreat, a rubbish tip and a prison. Now Mount Pleasant is to undergo another transformation, as part of the modernisation of the postal service.

Royal Mail is considering ambitious plans to redevelop its 120-year-old sorting office on the Central London site, in which large sections of it could be razed to make way for luxury flats and a giant new postal depot.

The proposals would represent the end of an era for Europe’s largest sorting office. It would be the biggest investment in a single sorting office in the UK and the largest investment in the Mount Pleasant site since the Post Office began operations there in 1887.

The sorting depot, which handles 3.4 million items of mail a day, would be moved into a new £100 million high-tech facility that would replace a car park on the site. The building could be funded by selling off part of the rest of the site to developers.

The site was originally part of open fields on rising ground above the River Fleet. In the 18th century a cold spring on the land was reputed to have medicinal properties and the site became known as Cold Bath Fields. The fields were later used as a rubbish tip and the site was ironically named Mount Pleasant.

In 1790 the land was cleared to make way for a prison, initially called the Middlesex House of Correction and later Clerkenwell Gaol, which closed in 1885. Two years later the Post Office adapted part of the site for use as a temporary parcel office. The first Post Office building devoted to the parcel post and the housing of postal stores was completed in 1890.

A spokeswoman said: “We are looking at investing significantly in Mount Pleasant. It remains vitally important to Royal Mail’s operations.”

She added that with the development of new technology the Mount Pleasant mail centre had ceased to provide the best working conditions for its staff, so it was important to explore options to improve it.

In a report due to appear today, PropertyWeek, the trade magazine, says that Royal Mail has appointed John McAslan, the architect, to draw up a plan for a 550,000 sq ft mixed-use development for part of the site fronting Farringdon Road.

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