The minimum deposit depends on several aspects and is quite flexible, changing according to client conditions, starting as low as £/€/$100. Trades at iFOREX can also be leveraged, although exact leverage rates vary according to the instrument and UK regulations.
Here is a quick example scenario: Take a £500 deposit and apply leverage of 30:1*. This means you could open trades with a face value of up to £15,000. The most important thing to remember is that leverage not only increases your trading power, but also increases risk, so it requires sufficient trading knowledge and experience. The minimum deal size when trading with iFOREX is roughly $2,500 (or the equivalent in pounds, euros and other currencies).
* Check out the Trading Conditions page to see the exact leverage rates available at iFOREX.