The Ministerial Code

The Ministerial Code is a kind of ‘rule book’ for Ministers. It describes the way ministers are expected to behave 

However the PM is expected to be responsible for ensuring the Ministerial Code is carried out.  So what happens if the PM does not uphold the standards expected by the code?  

For example: Did Boris Johnson mislead Parliament ? It looks like yes. The Ministerial Code States :

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”