Terra Firma Partners and Wellcome Trust, the medical research charity, have appointed Lehman Brothers to act as their financial adviser on a possible £10 billion-plus bid for Alliance Boots.

The groups made an approach to Alliance Boots’s board over the Easter weekend and they are understood to have since been granted access to the company’s accounts.

Detailed due diligence work is likely to begin within the next two days. A decision will then be taken on whether or not to launch a formal bid.

Terra Firma and Wellcome Trust are competing with Kohl-berg Kravis Roberts, the US private equity group involved in a joint offer for Alliance Boots with Stefano Pessina, the company’s deputy executive chairman and owner of 15 per cent of its shares.

The board of Britain’s largest chain of chemists agreed on March 30 to give KKR and Mr Pessina access to its books to undertake due diligence after they raised their initial bid to £10.40 per share, valuing the group at £11.4 billion.

The board added that it would allow other credible bidders the same access.

“Terra Firma and the Wellcome Trust confirm that they are at the early stages of assessing Alliance Boots,” the two groups said in a statement.

“No decision has been made regarding the merits of making an offer,” they added.

Wellcome has an endowment of around £13 billion and is now Britain’s biggest private equity investor, with around £6 billion in private equity, venture capital and hedge fund assets.

Its chief investment officer, the former Goldman Sachs banker Danny Truell, is leading the effort for Wellcome.

Terra Firma, led by financier Guy Hands, owns UK cinema chains and waste management firms but a bid for Alliance Boots would be much larger than the size of its usual transactions.

Celesio, a German company that owns Britain’s Lloyds Pharmacy chain as well as pharmaceutical wholesaling businesses, is also interested in bidding for Alliance Boots. However, it is not thought to have yet gained the backing of private equity investors and would face a series of regulatory problems in the event of a formal bid.

Alliance Boots, the company created last year from the merger of the 150-year-old UK retailer and Alliance UniChem, one of Europe’s largest pharmaceutical wholesaling operations, yesterday declined comment. Shares in the company closed up 0.6 per cent at £10.35.

Times Recommends

• C&G axed - 1,660 jobs to be lost
• UK house prices rise 1.1% as buyers return
• Mixed reaction to US banks repaying bailouts