LONDON (AP) — The Iron Lady is auction gold.

Speeches, books and outfits belonging to late British Prime Minister Margaret Thatcher — including her wedding dress — have soared above their estimated prices at a London auction.

Christie's is selling 150 lots Tuesday, and a further 200 in an online auction that ends Wednesday.

Thatcher's red prime ministerial dispatch box sparked a bidding war and sold for 242,500 pounds ($365,000). It had been estimated to reach between 3,000 pounds and 5,000 pounds.

A signed copy of the speech Thatcher made on becoming Britain's first female prime minister in May 1979 — declaring "Where there is discord may we bring harmony" — sold for 37,500 pounds ($56,460).

The blue velvet dress she wore to her 1951 wedding sold for 25,000 pounds ($38,000), and her copy of the collected works of Winston Churchill fetched 32,500 pounds ($49,000), 10 times its pre-sale estimate.

Branded the "Iron Lady" for her steely determination, Thatcher governed Britain between 1979 and 1990, transforming the country with her free-market policies.

She died in April 2013, aged 87, and the collection is being sold by her family — though some commentators felt the collection of power suits and iconic handbags should go to a museum.