The security minister has warned that the UK’s democracy is “under attack” after MPs were warned their mobile phones are a “potential goldmine for hostile states” seeking to harvest sensitive information.

Tom Tugendhat gave the stark assessment of the situation after Commons Speaker Sir Lindsay Hoyle issued MPs with advice from the Government’s National Cyber Security Centre to minimise their security risks.

“If hackers have switched on the microphone on one phone, everyone in the room might be overheard,” Sir Lindsay wrote to MPs.

His letter, first reported by the HuffPost UK website, comes after reports emerged of Liz Truss’s personal phone being hacked by agents suspected of working for the Kremlin while she was foreign secretary.

Sir Lindsay said: “As recent events have highlighted, hostile states continue to target Parliamentarians to gain insight into, or exert influence over, our democratic processes for their economic, military or political advantage.”

He added: “Our phones contain so much information: our messages, emails, contacts, photos and social media posts – including private, sensitive, personal, historic and sometimes even deleted data.

“They go almost everywhere with us, and have cameras and sensitive microphones built in, making them a potential goldmine for hostile states (as well as criminals and fraudsters) who wish to obtain sensitive information about Parliament and parliamentarians.”

Mr Tugendhat is leading a Westminster taskforce to address threats to the UK’s democratic institutions.

He said “our democracy is under attack” and that the Speaker “is right to warn all MPs”.

“That’s why I’m leading a new taskforce to bring together different groups that can protect our core sovereignty – the right to choose who leads us,” he said.