Especially Corbyn, though of course he couldn't "support it" outright because that would mean agreeing with Tories (and he couldn't oppose it outright without angering a lot of Labour members)
Corbyn is a lifelong Eurosceptic who voted against every expansion of EU power that came before him in his entire ~30 year career as an MP pre-2016. He only "opposed" Brexit in 2016 because he had to.