The Westminster consensus is that Boris will survive and Rishi will too, if he wants so to do. Whereas in the past law breaking without doubt would have been a resignation matter, the expectation today is that won’t happen. Those standards are long gone.
According to the Ministerial Code:
“It is of paramount importance that Ministers give accurate and truthful information to Parliament, correcting any inadvertent error at the earliest opportunity. Ministers who knowingly mislead Parliament will be expected to offer their resignation to the Prime Minister”
Presumably the PM would have to admit to himself he knowingly lied to Parliament and accept his own resignation. This seems unlikely.
Nevertheless Boris and Rishi will surely have to apologise to the House for their erroneous characterisation of events. The police have adjudged that Covid laws were broken. They will undoubtedly argue that this was not their understanding of the rules and therefore they “inadvertently misled the House”. The recent precedent for inadvertently misleading the House is to apologise to the House for doing so.
Alun Cairns was the last minister in 2016 to do that in response to a point of order:
“Further to that point of order, Mr Speaker, I am happy to clarify the position and, of course, apologise if I have inadvertently misled the House. …”
Failing that it will take a vote of the House, such as a vote of confidence to force a more dramatic outcome. A lesser motion of censure is also possible, though somewhat pointless. Tory MPs are not in the mood for a leadership election…