Second Jobs

I recently learned that MPs have been forbidden from having second jobs, the idea being that a second job would prevent them from focussing sufficiently on their work for the good of the country.

I don't know which dolt thought that one up, but I find it far more likely that MPs with part-time jobs will work better, since they won't be swayed by short-term populism, financial concerns over being granted a paid position as a minister or committee chairman or worries about re-election.
I would even venture to suggest that MPs should be required to have another job, or a fall-back job, confirmed by an employer (but without conflict of interest, such as working in a lobbying company), to ensure their immunity to such concerns.
They would also have more experience of working like the rest of the population, have networks outside of Parliament and the party apparatchiks and have less time for conniving to disenfranchise other voters in political meetings and conferences.