Yes, but the sub-thread here started with someone suggesting they'd be paying 50% tax, and when talking in terms of employees, it's not normal to include it. When including it, we're usually talking about total tax wedge rather than tax rate (e.g. see OECD Taxing Wages).

Even so, as noted, you'd not hit 50% even with payroll taxes at anywhere near the income levels stated. At the stated 100k GBP contracted salary, your "salary" including payroll tax would be 113,207 GBP, and your total tax wedge would be 41% (compared to 33% combined income tax and NI).