Big companies using vast wealth to wine and dine politicians to ensure they have their ear when needed, or putting massive resources into influencing policy through various means. Yes. Legal corruption.
But what about when a group (say representing the families of the victims of the Hillsborough tragedy) successfully lobbies individual politiians to hold an enquiry into something which then reveals lies that would otherwise gone unchallenged. Is that corrupt? I'd say no.
Or where large well funded charities use their money and power to provide a counterbalance to the interests of corporations in technical enquiries, consultations etc? Maybe?
I'm never sure where I think the line lies, but I do think there is a line.