Unless this is a hoax then whoever A) actually declawed the cat i.e the vet and B) assisted with declawing the cat i.e. vet nurse and C) owned the cat have broken the animal welfare law and are all liable to prosecution. If you know this happened as a genuine fact then you have a responsibilty to report it not only to the RSPCA but also to the Royal College of Veterinary Surgeons and the Police. Declawing is disgusting and any incidence of it happening in any European country, where it is banned unless for a specific medical reason for the cat, has to be stamped on immediately.
This makes me sick, bad enough it is happebning regularly in the USA and Canada, we do not want back door declawing to rear it's ugly head in the UK.