The UK’s largest charity, The Wellcome Trust, has emerged as the mystery company that has been stakebuilding in Marks & Spencer.

The Wellcome Trust has amassed a 2.5 per cent stake in M&S and confirmed it has bought 39.35 million shares in the retailer over recent weeks. It is thought to have spent about£110 million.

Speculation had been circling the City over the past two days that a mystery stakebuilder would make a bid for M&S.

Businessman Warren Buffett and France’s Halley family, which has a stake in French grocer Carrefour, were both rumoured to be potential bidders. The Wellcome Trust is unlikely to make a bid for M&S.

In a statement, Wellcome Trust said the investment is “part of Wellcome Trust’s long-term investment portfolio”.