Clifford Chance (CC) is leading a quartet of legal advisers to secure principal roles on the £7bn cash injection into Barclays from the Middle East.

CC fielded a team under corporate partners Guy Norman and Patrick Sarch, regulatory partner Chris Bates and capital markets partmer Simon Sinclair. The instruction extends a growing list of mandates CC has handled this year for Barclays – one of its core clients – including acting on its high-stakes purchase of Lehman Brothers' US business.

Norman also advised Barclays on its opt-out of receiving a capital boost from the UK Government after planning to raise more than £6.5bn of tier one capital without state help. Barclays had to obtained the opt-out after the Government this month unveiled its plan to recapitalise a group of the UK's largest banks, which introduced tougher standards on bank financing.

Meanwhile, Latham & Watkins advised Qatar Holding, which invested £3.8bn into the UK bank. Qatar Holdings is a subsidiary of the Qatari Investment Authority (QIA).

The US law firm fielded a London team under M&A partners Nick Cline and Graeme Sloan, with banking partners Bill Voge and Chris McFadzean assisting. Cline and Sloan were also earlier instructed by the QIA when Barclays raised £4.5bn in July.

Freshfields Bruckhaus Deringer has also won a role for the bookrunners, Credit Suisse and JPMorgan Cazenove. Freshfields' team was led by corporate partner Julian Makin and included partners Will Lawes, Colin Hargreaves and Sarah Murphy.

Allen & Overy (A&O) is acting for the Abu Dhabi royal family, which has also acted as an investor into Barclays. The A&O team includes international capital markets partner Jonathan Mellor, corporate partner Louise Wolfson, tax partner David Hughes, New York corporate partner Kenneth Rivlin and regulatory partners Paul Philips and Douglas Landy.

The transaction will see Qatar and Abu Dhabi secure a 30% stake in the British bank.