Not enough saints to go around
Plumbers are paid well because they wade through effluent. In their own way, so do those in politics (indeed, one parliamentary candidate recalled being sent a photo of her election leaflet covered in a large human turd). Relying on public spiritedness alone to guide people into politics is as foolish as hoping goodwill will be enough to persuade someone to spend a life unblocking toilets.
In a previous paragraph
A lack of money also dilutes the quality of the politicians tasked with putting those ideas into practice. When salaries were first introduced for MPs in 1911, they amounted to £400 per year or roughly six times the average wage of the time. Now an mp earns around £84,000, just over double the average full-time wage. (The days of being able to boost pay via dodgy expense claims are long gone, too.) Meanwhile, incomes for high-flyers in professional services have exploded in the past few decades. Lawyers, bankers and even accountants now command large salaries, pulling well ahead of former fiscal peers such as doctors and politicians. The opportunity cost of a career in politics is huge for the most able.
A lack of money leaves much of politics the preserve of those who are rich, mad, thick or saintly. Sadly for Britain’s body politic, the saints are outnumbered by the rest.