Workers are effectively cancelling out their entire annual leave by using phones and iPads to work outside of office hours, it has been revealed. A survey of more than 1500 managers in the UK found that a majority were spending 29 extra days a year working on their handheld devices, cancelling out their statutory holiday time.Four out of five of those polled by the Chartered Management Institute said they worked at least an additional hour every day, rising to three hours for one in 10 of those polled. Most managers surveyed reported a link between working long hours and health problems and burnout.Ann Francke, chief executive of the institute, said: "Productivity will continue to suffer unless employers train their managers to prevent overwork and strike the necessary work-life balance."The so-called "always-on" working culture has previously been blamed for a spike in neck and muscle pain caused by working on handheld devices. ..