They're posting every MP who voted in favor of it on Twitter. Some of the posts are simply unbelievable. There's one I saw (and lost as it refreshed) where they had several newspaper clippings over the last few years in one area of Britain that stated something like:
Leaving the EU will roll back our Environmental Protections
which was followed by a response article headline:
Completely Unfounded Fear Mongering by the Left
which was followed by the headline a few days ago:
14 BEACHES YOU CAN NOT SWIM AT DUE TO POLLUTION