The three possible cash bidders for Safeway are said to have been approached by a mystery intermediary offering to sell them a 12% stake in the supermarket group, the Telegraph reports.

The intermediary is thought to have contacted Wal-Mart/Asda, retailing entrepreneur Philip Green and US buy-out group Kohlberg Kravis Roberts, suggesting he could arrange for them to buy shares owned by American fund management groups Fidelity and Alliance Capital Management, the paper said.