The TRONC system (although it was introduced in the early 20th century) didn’t become widely implemented in the hospitality industry until circa 2000 I believe. At this time most tips and many bills for that matter were paid in cash.
Wait staff generally kept their individual tips and tipped out other staff members such as the table clearers etc. All staff were responsible for declaring cash tips on their tax return, although I’m not sure how many did this!
Around 2000 things changed a bit and more people were paying with cards.
The current system was made law in 2023 I think. If the restaurant pools all tips and re-distributes to all staff (which many do) the employer is then responsible for reporting these amounts, including any deductions for employee tax.
So if you choose to give a cash tip ‘under the table’, the inland revenue could lose out and the other staff who rely on the tips, such as the dish washers the poorest, often very young guys would also lose out.
Generally it’s a fair system if you understand that service is part of all staff’s the wages but it’s dependent on how well they perform.
One very good argument for keeping service charge as an addition to the bill total is that it incentivises the staff to work harder for the customer. If the service was absorbed into the food price you would not have the option to refuse should the service be awful.
I think there are so many posters on here who know nothing about the industry and to suggest all a waiter does is take food from the kitchen to the take says it all.
FYI - If tips are discretionary there is no VAT added on the service element.
If you check your total you will see that the VAT isn’t 20% of the total bill.