Macfarlanes has scored a coveted role on the £9.7bn takeover bid for Alliance Boots, advising executive deputy chairman Stefano Pessina on his part in the takeover bid.

Macfarlanes corporate partners Tim Lewis and Graham Gibb are advising Pessina, as he put forward a joint bid with US private equity giant Kohlberg Kravis Roberts & Co (KKR).

Pessina took a stake understood to be around 15% of the combined group following the merger between Boots and Alliance UniChem last year. He was the former executive deputy chairman of Alliance UniChem and was instrumental in the £6.5bn tie-up.

The instruction marks one of Macfarlanes' most high-profile mandates since 2005 when it advised Pernod Ricard on its £7bn takeover of drinks rival Allied Domecq.

Slaughter and May has landed the lead role for Alliance Boots on the KKR bid, after edging aside Allen & Overy, which was appointed as co-lead counsel to the group with Slaughters following its merger.

Clifford Chance (CC) joined Simpson Thacher & Bartlett to advise KKR. Although the private equity house has historically turned to Simpson Thacher for advice in the US, its preferred European adviser has been less clear cut, with Freshfields Bruckhaus Deringer among the firms to have acted on its behalf in the past.

Corporate finance partner Daniel Kossoff led the CC team advising KKR, with corporate partner Gregory Conway leading for Simpson Thacher.