Jeremy Hunt says he wants the NHS to expand so that more patients get the best care when they need it. But is the health secretary's goal of week-round provision realistic when the health service is already struggling to make an unprecedented £20bn in efficiency savings? And what is the evidence that more staff at weekends will make a difference? Wesley Stephenson investigates the case for weekend working in the NHS and asks what lessons we can take from hospitals in England already moving towards seven-day services.