The UK was one of the top 3-4 nations by voting power (depending on the time) in the 27-member EU and a very important player in EU politics. Their negotiating power is evidenced by the fact that they were able to secure opt-outs from a number of treaty obligations.
In the past! Over time less and less was decided by voting and we saw what the UK's influence was worth when Cameron took voters concerns to the other leaders. Answer: shut up and do as you are told.
The EU hasn't been interested in votes for a long time and will certainly be even less interested in future.
