How threatened is the PM by new partygate probe?

MPs have approved the plan to open an investigation into whether Boris Johnson misled the House over the infamous lockdown parties.

So where does this now leave a prime minister who insists he won’t resign amid cries of a constitutional crisis?

Political Editor Robert Peston tells Tom Bradby what you need to know as he reflects on some astonishing scenes in the House of Commons.

In a typically forensic discussion, Robert evaluates the chances of Johnson holding onto power and the obstacles ahead for him, before identifying the Tory MP he sees as a dark horse among the PM's potential replacements.