NHS policy in England is directed from the centre by the Department of Health.

But local health bodies, known as primary care trusts, are in charge of providing and commissioning services, controlling the majority of the budget.

The number was halved to 152 in October 2006 to bring them in line with social services bodies.

PCTs are overseen by 10 regional organisations called strategic health authorities.

Recently GPs in some areas have been handed control of the purse strings by PCTs to commission services as the NHS tries to encourage more care to be administered outside hospitals.

Health is essentially a devolved function, meaning the other parts of the UK have different policies and structures.