Alliance Boots is reportedly considering opening up its books to a potential rival bidder to Kohlberg Kravis Roberts' (KKR) £10.2-billion offer.

Numerous newspaper reports over the Easter weekend claimed the Wellcome Trust and private equity group Terra Firma have asked to view the books of Britain's biggest pharmacy chain. It was also rumoured that Celesio, the German owner of the Lloyds pharmacy chain, is considering a bid.

KKR upped its offer last month after an earlier bid was dismissed as too low.

Alliance Boots has already opened its books to KKR, which had teamed up with Boots' deputy Chairman Stefano Pessina, who already owns 15% of the retailer.

A decision on whether Wellcome and Terra Firma will be allowed to see the books is expected by the end of this week.

The Wellcome Trust is the UK’s biggest charity as well as the country's largest investor in private equity. And Terra Firma owns UCI and Odeon cinemas among its investments.

Deputy chair, Pessina is rumoured to want to take the company private and develop it away from public scrutiny. But trade unions are opposed to the deal, saying a private equity deal could lead to asset stripping.

The company has been busy integrating the legacy infrastructures owned by the two companies before they merged last year.