John McDonnell says he’d send Jeremy Corbyn to Buckingham Palace in a taxi to tell the Queen “Labour is taking over” if Boris Johnson loses a vote of no-confidence.
Turning to the Queen to help resolve matters in Parliament would be a drastic last-ditch effort to end the political turmoil.
The Shadow Chancellor, speaking at the Edinburgh Festival, said he was reluctant to “drag the Queen into this” – but he would if necessary.
Prime Minister Mr Johnson has said he might not quit if he lost a vote of no confidence.
As political parties try to form a new government, he could hang on for 14 days, automatically triggering a general election.
It’s thought Mr Corbyn will table a no-confidence vote in the Autumn to prevent a No-Deal Brexit.
Parliamentary experts have warned the PM that the Queen is “is not a decorative extra” and may be forced to “dispense with his services herself”.