The Queen will be asked by the government to suspend Parliament days after MPs return to work – and a matter of weeks before the Brexit deadline.
The BBC's political editor, Laura Kuenssberg, says it will make way for Boris Johnson's new administration to hold a Queen's Speech – laying out the government's future plans – on 14 October.
But it means MPs are unlikely to have time to pass any laws that could stop the prime minister taking the UK out of the EU without a deal on 31 October.
A No 10 source said: "It's time a new government and new PM set out a plan for the country after we leave the EU."
The idea of shutting down Parliament – known as prorogation – has caused controversy, with critics saying it would stop MPs being able to play their democratic part in the Brexit process.
Laura Kuenssberg said only a small number of government ministers knew about the plan and it was going to cause a huge row. (BBC)