Discourage MPs from having second jobs; change their salary into a deductible allowance.

Fellow citizens of the UK, it is time to make our MPs focus on their primary duty and spend their time and energy serving us, their constituents and country, instead of serving themselves and associates. Too many have second or even multiple other jobs, filling most of their time and attention at the expense of their real purpose as our MPs. Effectively they are too often just cocking a snook at their MP's responsibilities whilst chasing their selfish personal enrichment.
I propose that all MP's salaries are changed into an MP's Allowance, which is at the same rate as their current salary but DEDUCTIBLE against any other earnings, pound for pound. If they are paid £30K for private work then their MP's allowance is deducted by £30k, and so on, all the way up to losing it all if their private pay exceeds the allowance. This will at least help deter the inauthentic MPs who hitch a lift on the currently overcrowded gravy train!