London: Former British prime minister Margaret Thatcher's famous red ministerial box fetched 242,500 pounds ($364,600, 334,000 euros) at a sale of her possessions held Tuesday in London by auction house Christie's.

Initially expected to sell for between 3,000 and 5,000 pounds, auctioneer Jussi Pykkanen finalised the sale to an unidentified buyer with a bang of his hammer, to applause from the audience.

The box, in which the late Conservative leader would carry confidential documents, is one of the most iconic of around 200 of Thatcher's personal belongings offered for sale by Christie's.

Many have been advertised online since December 3, with the sale due to end Wednesday.

Items which belonged to the "Iron Lady" have often sold better than the clothes she wore.

A sheet featuring a typed prayer attributed to St Francis of Assisi and signed by Thatcher, which she quoted on first arriving in Downing Street in 1979, sold for 37,500 pounds, despite an initial estimate of between 600 pounds and 900 pounds.

Her blue velvet wedding dress, valued at between 10,000 pounds and 15,000 pounds, went for 25,000 pounds to a buyer in Oman.

Some 200 buyers followed the sale online and many others by telephone, including prospective bidders from Austria, South Korea, Australia and the United States.

The sale of Thatcher's clothes revealed her "secret passion" for fashion, curator Meredith Etherington-Smith said.

Thatcher was the daughter of a seamstress and as a child she and her sister made their own clothes, she added.

"When she became the first woman prime minister, she used clothes as a way of emphasising her power," Etherington-Smith explained last week.

"Every time there was a photo opportunity, she was beautifully dressed, immaculately coiffured, with a nice handbag, and she looked what she was: a powerful person."

Thatcher led the country from 1979 to 1990. She died in 2013 at the age of 87.