Public employee salaries

Tim Worstall is quoting a TPA piece and it has even made the radio news:

Over 800 town hall employees make more than £100,000 a year. Some even
make more than Polly, if you can believe that.

Given that government, national and local, is a necessary evil it is in our own interests that we employ the best people and pay them well. The problem is that there isn't a real benchmark to decide what they are worth. There pay is therefore decided by some committee who come up with typical jobs in the private sector.

I have a much better idea that will demonstrate how much they are really worth. Every 5 years anyone earning more than, say, 1.5x the median salary, should be given 3 months to find a job in in the private sector. They can either accept the job or have their salary set at the level of that job offer. If the don't get an offer they should be paid 1.5x the median salary and take a 10% cut every year until they can either get a job offer and get their salaries set to the new offer or to the minimum wage.