Prevent MPs voting on matters they have a connection or vested interest in.

It should be written into parliamentary law that any MP cannot vote on matters for self interest. Personal gains. family members interest. or personal gains.

It's a matter for individual MPs, rather than the Government or Parliament as a whole, to decide on which matters to vote, and how to vote.

In any case, the House of Commons already has a Code of Conduct for MPs. Under existing rules, MPs are already required to register and declare financial interests. If there is a conflict between their personal interest and the public interest, they must resolve it straightaway and in favour of the public interest.

Complaints that a Member has breached the Code of Conduct are examined by the independent Parliamentary Commissioner for Standards.

You can find the Code of Conduct for the House of Commons here:

https://www.parliament.uk/mps-lords-and-offices/standards-and-financial-interests/parliamentary-commissioner-for-standards/code-of-conduct-and-rules-of-the-house/