Paying Tips at Restaurants

H there,

Does anyone know if there is any legislation /case law covering paying tips at restaurants, if you pay cash can these be reclaimed, my belief is that they are not an allowable business expense and since no receipt issued to confirm so they can not be claim, just can't see anything from Revenue confirming so

For future scenarios... Maybe when asking for the bill you can ask for an x % service charge to be applied... most restaurants will auto apply 10% for parties of 6 or more. So their billing system should be able to apply it.