Think about New Labour. The Blair era.
They traded nicely for quite a long time on this before they were seen through. Once they did, trust in politics plummeted and now you'd struggle to find anyone who listens to a politician without a voice in the back of the head saying 'they're a politician and they have an agenda to manipulate you, which is truth/fact optional'.
It's going to happen here, and it won't be that long. The Harry Miller case is the first giant step. There is going to be a major Oh Fuck moment where suddenly everyone realises the info they have based their policies on is firehosed political agenda and they're wide open to legal challenge. On the plus side, once the UK gets wise to it, another political lobby won't be able to pull this.