Clifford Chance (CC) has bagged a key mandate opposite magic circle rival Slaughter and May to advise on the £9.7bn takeover bid for Alliance Boots by Kohlberg Kravis Roberts & Co.

CC joined Simpson Thacher & Bartlett to advise the US private equity giant on its offer for regular Slaughters client Alliance Boots, which rejected the bid earlier this week (12 March).

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

The instruction will be seen as a coup for CC. Although the private equity house has historically been represented by Simpson Thacher, 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.

Significantly, CC advised KKR alongside Simpson Thacher on its acquisition of Philips' semiconductors business last summer in a deal that valued the business at €8.3bn (£5.7bn).

One partner at a rival firm commented: "It's a great deal for CC to be involved in. [Kossoff] has done quite a bit of stuff for them over the years, but not very much in the UK market. This deal has a way to go yet, so it will be interesting to see how it pans out."

Slaughters is acting for Alliance Boots, with corporate partners Frances Murphy and Robert Stern leading the team. Slaughters landed the role after edging aside Allen & Overy (A&O), which was appointed as co-lead counsel to the group with Slaughters following the £6.5bn merger of Boots and Alliance Unichem last year – a deal on which A&O advised Alliance.