Boris Johnson rejects calls to let caretaker premier take over

British prime minister Boris Johnson, watched by wife Carrie Johnson (centre holding daughter Romy), reads a statement outside 10 Downing Street, London, formally resigning as Conservative Party leader after ministers and MPs made clear his position was untenable (Gareth Fuller/PA)

Boris Johnson is refusing to heed calls to let a caretaker British prime minister take over, as would-be successors are weighing up leadership bids.

There is growing pressure from senior Conservatives for Mr Johnson to step down immediately as prime minister and not wait for the election of a new leader.