Chinese companies building 5G networks could create “chaos” in the UK by hacking into everything from train systems to energy services, a former security minister has warned.

Admiral Lord West, an ex-First Sea Lord who served as security minister under Gordon Brown, told the Sunday Telegraph that Chinese companies could provide Beijing with a backdoor to control Britain’s infrastructure.

“In the worst case scenario, we could have great vulnerabilities in all sorts of areas,” he said.

“All our communications could be hacked. China could switch things off, shut things down. For instance, it could suddenly stop algorithms that train timetables run on…you can just see the chaos that could ensue.”

Lord West isn’t calling for a blanket ban but wants the Government to create a unit that would monitor the risks posed by Chinese companies and report those concerns directly to the prime minister.

“There needs to be very clear ministerial guidance on this,” he said. “We need to know what the risks are. At the moment, it’s all being left a little bit in the air.”

China is currently a world leader in developing 5G, a next generation mobile internet technology that promises to deliver faster download speeds and better connections. The technology, which is being trialled in the UK, could speed up the creation of “smart cities” in which everything from traffic signals to driverless cars are linked.