How can this possibly be legal?

One of the measures which is standardly used to prevent corruption is making people in positions of power declare their interests. For example, if a politician is deciding which company gets a government contract, and the politician works for one of the companies in the running, they have to declare it and the decision may be delegated to someone else. If they don’t declare it and get found out, they get into trouble. It is fairly obvious that a system lacking this feature would be open to abuse.

One thing which seems to be allowed, however, is for a politician to take a job with a company after having used the power entrusted to them by the electorate to benefit said company. Private Eye reports on this sort of thing all the time. They call it the Revolving Door. I can’t see any principled reason to think that undeclared future interests compromise the integrity of the politicians involved much less than undeclared present interests would.

It seems to me that it would be pretty easy to put a stop to it. You say that politicians giving contracts to companies have to declare an interest or either face trouble or not take a job with the company for, say, five years. And if people keep waiting out the time limit and then immediately taking jobs with companies they’ve helped, we smell a rat and extend the time limit. But perhaps I’m missing something and a rule like this would be impossible to put into practice.