Paying below Minimum wage?

Sorry but it is perfectly legal. A lot of small firms and many in the building trade employ people on a self employed basis. They give you the work and you pay your own tax and NI contributions. It is up to you to earn more than the minimum wage. This system has been in place for many many years. A lot of hairdressers who work in salons do this. the salons give them the appointments and it is up to them how many Hours they work, but they are responsible for their own taxes and NI.