A trio of magic circle firms have advised on Santander's £3.75bn bond sale, in one of the biggest UK residential mortgage-backed securities deals since the financial crisis.

Slaughter and May took the lead role for Santander, while Allen & Overy (A&O) acted for the joint bookrunners, which comprised Barclays Capital, JP Morgan, Morgan Stanley and Santander Global Banking & Markets.

Linklaters also won a role on the transaction, advising the trustee, while Cleary Gottlieb Steen & Hamilton provided US advice to Santander.

A&O's team was led by City international capital markets partners Vanessa Hardman and Salim Nathoo. A&O counsel Hank Michael advised on US aspects of the deal, while partner Richard Tredgett advised on derivatives. The firm also advised on tax aspects of the deal.

The Slaughters team was headed by City banking and finance partner Guy O'Keefe, while capital markets partner Jasper Evans took the lead role for Linklaters.

A&O's Hardman said: "The deal involved an issuance under a Santander UK programme, which it acquired after its acquisition of Alliance & Leicester in 2008. We have been involved in the programme since its establishment, including on the four issuances last year.

"The deal is the first issuance under the programme this year. It has had a lot of attention in the press and was oversubscribed by investors, which is a good sign that the UK securitisation market is becoming active again."

This deal was issued through Santander's Fosse securitisation programme, which was set up in 2006 and which saw A&O advise legacy Alliance & Leicester.