Clifford Chance (CC) and Mayer Brown have taken lead roles on JP Morgan's £495m acquisition of Lehman Brothers' former London headquarters.

The 25 Bank Street building in Canary Wharf will now serve as JP Morgan Investment Bank's new European headquarters, with the bank granted a 999-year lease on the building, which has more than one million sq ft of floor space.

The building's current tenants include the Financial Services Authority, NYSE Euronext and Jones Lang LaSalle. However, it will be completely vacated by March this year and will then be occupied exclusively by JP Morgan.

CC advised longstanding client Canary Wharf Group on the sale, with the magic circle firm fielding a team comprising real estate, corporate, insolvency, finance and tax lawyers.

Real estate partner Tony Briam led the team which also included partners Andrew Forryan (capital markets) and Mark Poulton (corporate), with insolvency partner Nick Frome, finance partners Andrew Brozman and Jennifer DeMarco and tax partner Sarah Squires also advising.

Mayer Brown advised JP Morgan, fielding a team led by real estate partner Jeremy Clay, who worked alongside fellow real estate partner Anita Jones and Nick Marshall. The team also included corporate partner Drew Salvest and Richard Page, as well as insolvency partner Ian McDonald. Chris Fellowes and Peter Steiner advised on construction and tax matters respectively.

Briam said: "We were very pleased to work with Canary Wharf Group on this high-profile transaction involving a real estate focused multi-disciplinary team bringing this to a successful conclusion. The deal is a great economic boost for London and the wider UK economy."

Clay commented: "We were delighted to help JP Morgan in relation to the acquisition of their new European Investment Bank Headquarters, and their continued investment in the UK."

The deal follows Clifford Chance's involvement in advising Canary Wharf Group on the recent office occupations by KPMG, Shell and Fitch.