As Rishi Sunak concludes tortuous Northern Ireland deal, Boris Johnson watches and waits

Those who have spoken to Johnson say he will consider his options when the shape of the deal is obvious. Photograph: Rex/Shutterstock/EPA

Rishi Sunak is approaching what might be his toughest party management challenge yet – the conclusion of a long negotiation to find a way through the tortuous issue of the Northern Ireland protocol.

But whether he is able to keep his MPs in line is likely to depend on whether Boris Johnson sees the protocol as his moment to stage a key intervention that could launch a potential comeback.