Michael Geoghegan, chief executive at HSBC, has also been named in reports among those executives who may succeed Mr Green to the post.
He is expected to stand down from the role in 2011 after being named as the UKâs new minister for trade and investment on September 7th.
The unpaid position will involve promoting the UK as a destination for international trade as well as an exporter of services and goods.
Mr Green said: âIt is an honour to accept this new role with Her Majestyâs government, serving Britain in the vital areas of trade and investment.
âIn an increasingly competitive and international world, trade and investment are ever more critical to Britainâs economic success and I am delighted to be joining the government at this exciting and challenging time.â
He is expected to step down from the position before the end of 2010.
By Jim Ottewill