what is the spreadbetting margin requirement?

Margin Requirement is the underlying principle multiplied by the margin factor. For example if you want to trade BP at £10 / point and the price quoted by the spread betting firm is 450p this is the equivalent of 1000 shares at 450p, which equates to £4500. The margin factor is 5% for B.P, so in order to make this bet, you must have 5% of £4500 in your account which equates to a margin requirement of £225.