Royal Mail boss Moya Greene faces a "health and safety" challenge from the Communication Workers Union (CWU) after she mooted the idea of introducing a driverless van service in the future. The union, which represents more than 110,000 Royal Mail workers, told IBTimes UK the chief executive should concentrate on tackling "real resourcing issues" within the FTSE 100 firm.

"While the CWU has always supported the sensible use of modern technology, the issue of driverless trucks clearly raises a mass of practical and health and safety issues for our members, for consumers and the wider public," a CWU spokeswoman said.

"The CWU would much rather the CEO concentrated on tackling the real resourcing issues the business currently faces and focus on how to improve the service our members currently provide. At a time when our members are facing unprecedented pressure in relation to workload, we also find Greene's assertion that staff are so happy they walk with a spring in their step, baffling and insensitive."

The warning comes after Greene told the Confederation of British Industry's (CBI) annual conference in London that she would "love to see how sensory technology is working, so that we can probably see a day when we're going to have driverless trucks". Greene, who took charge of the postal giant in 2010, also said she was open to using unmanned aerial vehicles (UAV), known as drones, for deliveries in remote areas.

Similar programmes have been trialled in Singapore and the US Federal Aviation Administration (FAA) has given the green light to deliveries of medical supplies via drone to remote locations. The regulator has also given online retailer Amazon approval to begin drone delivery trials.