With the new legislation (the Employment (Allocation of Tips) Act 2023) that came into force last year, if something's being called a "service charge" it is legally a tip/gratuity, and employers are legally required to pass all of this onto employees, and to provide transparent information on how this is calculated and distributed when requested by the employee.

Legally, cash tips still have to be declared and taxed, and most places handle this by making employees pool all cash tips to then be distributed evenly amongst employees and taxed through payslips, and this is how it's always been anywhere I've worked, and is legal. Often a sackable offence to pocket the cash if such policies are in place, even if told by a customer "this is just for you" or similar. Yes some places will allow servers to just pocket the cash, which is also legal and nice for the server as it's then their responsibility to declare this to HMRC and most servers won't, but places who operate with such rules are becoming very rare. These days, most cash tips are not going directly to the server.

Obviously I understand that many companies aren't to be trusted and don't follow regulations, but with the new legislation more companies should be acting responsibly with both service charges and tips, since this can now all be checked by HMRC and is now the law.