SJ Berwin has scored a role on the development of the prestigious London residence One Hyde Park by securing a £1bn funding facility for the process.

SJ Berwin won the mandate to advise Guernsey-based property development business Project Grande after it gained funding to redevelop the Bowater House site in Knightsbridge.

The newly-developed site will consist of around 80 upmarket apartments and three retail units, as well as hotel and leisure facilities. At least one of the penthouse apartments – some of which are up to 20,000 sq ft in size – is reported to have been sold for more than £100m, making it the most expensive apartment in the world.

Property partner Bryan Pickup led the SJ Berwin team, which included tax partner Heather Corben, finance partner Jeremy Cross and corporate partner Graham Nicholson.

Eurohypo, advised by Clifford Chance real estate partner Mark Rees Jones, provided more than £1bn worth of debt financing for the transaction.

Project Grande is a joint venture between CPC Group and Waterknights Developments. SJ Berwin advised the consortium as a whole, as well as CPC individually. Waterknights was advised by Fried Frank Harris Shriver & Jacobson, led by London corporate partners Jerry Walter and Rob McBride and property partner Nigel Heilpern.

Dundas & Wilson partner Carl Asser advised the consortium on the construction issues.

The development has been designed by the Richard Rogers partnership, which was also responsible for Canary Wharf and the National Assembly for Wales.

Pickup commented: "The initial acquisition was made in March 2005 and has involved getting consent from a raft of people, including planning permission, the go-ahead to relocate the Tube entrance and permission from the highways and the royal parks."

SJ Berwin has advised CPC on most of its London deals, including advising the group on the initial acquisition of the site. It also advised CPC as part of a consortium on the acquisition of Chelsea Barracks for a reported £600m.