Free margin

The executing-trades page defines it as equity minus margin, and then warns that the broker's conditions decide whether floating profit, floating loss, or both, are counted in the equity used for that calculation. A pending order also consumes margin on that platform, so free margin falls when the order is placed, not only when it fills. Free margin is not cash that can necessarily be withdrawn. Withdrawal rules are the broker's, and a UK retail close-out can still close positions if net equity falls below half the required margin.