[kwhitefoot]

The highest marginal tax rate in the UK is 45% [1] and you only pay that on income above 125 140 GBP.

Where did your 60% come from?

[1] https://www.gov.uk/income-tax-rates

[psychphysic]

National Insurance is a tax, additionally after 100k you start losing your personal allowance.

The net effect is an effective tax rate much higher than the nominal rate.

You lose other benefits to but they aren't factored in as depend on if you have kids or not etc.