Planning officers are members of the royal town planning institute. It requires post graduate degree and experience in practice before you are eligible to join. The role and duty of the RTPI is set out in an act of Parliament. Planning officers are bound by a code of conduct. You can report planning officers to the institute, if proven they will be struck off. The list is public. The number of bad eggs is very small. No one goes into being a planning officer motivated by money. They all want to make the world a better place for people like you OP. Foolishly.
……..and as such, any bribe would also be required to be so large that the recipient didn’t need to work again; perhaps not that likely to secure a positive outcome for Mrs Goggins’ conservatory application or whatever it was that got the OP riled.
With many many years both as LPA Planning Officer and private developer behind me, I can honestly say it isn’t a problem; with one offer of a bottle of scotch and a free car wash all that spring to mind…………but Councillors and estate agents, that another story!