Over 400 items belonging to Margaret Thatcher, the first woman prime minister of Britain, have been up for sale and bidding, Christie's auction house has announced. The auction features 186 items and will take place at Christie's London in King Street on 15 December.

An online only sale featuring about 232 items started early this month and will run until 16 December, the company said. Both the sales include items from the public and private lives of Thatcher.

"The Iron Lady's collection provides a rare glimpse into her life over several decades. From her fashion and accessories to much-loved porcelain military figurines and novels, this sale encompasses her style, personal collecting tastes and items from her political life," the company said in a statement.

With estimates starting at £100, the sale is said to provide a wealth of opportunities for international collectors. Some of the key objects include Thatcher's red leather dispatch box embossed with the cypher of Queen Elizabeth II, signed copies of key speeches and presents from president Ronald Reagan and other international leaders.

Thatcher's jewellery, clothes and handbags, as well as her private collection of porcelain, silver and gold boxes are some of the personal belongings that will go under the hammer. Among the most personal lots is Thatcher's wedding ensemble comprising a midnight blue velvet gown with a sweetheart neckline and long sleeves, a soft brimmed cap with ostrich feather and matching muff. The outfit is expected to fetch £10,000 to £15,000 at the auction.

Fashion accessories of Thatcher, who died of stroke aged 87 in 2013, have attracted some of the highest bids so far. These include a sapphire, ruby and diamond-mounted multi-strand pearl necklace, a diamond set with gold coin pendant, a yellow diamond butterfly brooch and an antique Roman bronze brooch among others. All the items that will be auctioned have been opened to public viewing at the Christie's London headquarters ahead of the sale.