As Britain's first woman prime minister, much of the population considered Margaret Thatcher's colourful suits to be the epitome of style.

Several of these iconic outfits will now feature as part of Christie's highly-anticipated London sale, which will be held in its South Kensington showroom on September 3.

Christie's believes this is the first time Thatcher's clothing has been offered

The suits were all worn when Thatcher served as the minister of education between 1970 and 1975, after being appointed by Edward Heath, whom she would later defeat in the Conservative Party leadership election to become leader of the opposition.

The suit she wore on the very day she was confirmed as leader of the Conservatives, and therefore the first female leader of a major political party in the UK, will feature in the sale. The jade green wool outfit is composed of a jacket and silk topped dress with a neck tie and belt, and is labelled "Mansfield Made in England". It is expected to sell for £1,000-1,500, an estimate shared by all of the Margaret Thatcher items at auction.

The values appear conservative, considering one of her handbags sold for £103,000 in 2000.

Perhaps the most exciting lot among the collection is the Iron Lady's cocktail ensemble, which was designed by Susan Small, whom Thatcher often cited as her favourite designer. The subtly lavish outfit is composed of a skirt and cocktail coat of gold and lame stripes, with a blouse of ivory embroidered crepe.

With this year seeing London hosting the 2012 Olympics as well as the Queen's diamond jubilee, the London Sale features as part of Christie's A Festival of London, which consists of a selection of exhibitions around the city that have been specially curated by the team behind the auction. These events will run through to early 2013.