It’s understood the same as a middle finger would be, except more Britishly.
Growing up, the story was that it came from when longbows were peak weaponry and the French were chopping the fingers off of captured English archers - the V sign was saying something like “fuck you, I can still shoot you”. There’s insult/defiance/threat in there but it’s not like throwing down the gauntlet (to be clear, we don’t do that gesture any more).
Good, I guess.