Create an Independent Office of Parliamentary Standards

Although MPs are in principle governed by a Code of Conduct, many Tory MPs simply breach that Code because they know that there is typically no sanction for such a breach. The most egregious example was probably the UK Internal Markets Bill, where a very large number of Tory MPs voted to break International Law, in clear breach of III.5 of their Code , namely " Members have a Duty to Uphold the Law "

https://publications.parliament.uk/pa/cm201719/cmcode/1882/1882.pdf 

Such a massive breach of the Code tells us that the Parliamentary system used to ensure that MPs obey their Code of Conduct has failed, and more recently of course, the Prime Minister has himself directly breached III.5  of the MPs Code of Conduct ,by holding parties in No 10 Downing Street at a time when that was forbidden by law - and initially lying about that - which is a further breach of the " Honesty " provision of the Code.

Since the existing system does not work to ensure that MPs obey their own Code of Conduct , it seems clear that the People should set up an Independent Office of Parliamentary Standards where MP's breaches can be both reported, and considered for further action as appropriate.