Source: BBC News
London has become one of the biggest centres for Islamic finance in the world, with five Islamic banks, and many others in the high street offering Islamic financial products, or "windows" as they are known.
The growth of Islamic finance has been an unexpected outcome of the attacks on the World Trade Center of 11 September 2001.
Islamic finance is based on rules from Islam's holy texts - the Koran. Scholars claim the fundamental difference to conventional banking is that Islamic finance is more ethical.
First it bans any form of "riba" or interest, preventing consumers being exploited by high rates of borrowing.