Britain and China have signed a deal for the first clearing service for yuan trading outside of Asia.The move will make yuan, or renminbi, transactions in London's financial centre more efficient and quicker. In a statement, Britain's Treasury said the agreement between the Bank of England and the People's Bank of China further strengthens London's position as the Western centre of renminbi trading.Hong Kong, the former British colony which is now a special administrative region of China, is the largest centre for offshore trading of the yuan.