Pro-Brexit placards are seen outside the Houses of Parliament in London, Britain, March 26, 2019. REUTERS/Alkis Konstantinidis

LONDON (Reuters) - The chief of the 2016 “Vote Leave” Brexit campaign said on Wednesday that opponents of European Union membership should start rebuilding the network and that they would win by a bigger margin if there was another referendum.

In the June 23, 2016 referendum, 17.4 million voters, or 51.9 percent, backed leaving the EU while 16.1 million, or 48.1 percent, backed staying. Ever since, opponents have pushed for another referendum.

“Start rebuilding our network now,” Dominic Cummings, who ran the Vote Leave campaign, said in a blog. “Beating them again and by more will be easier than 2016.”

Cummings said many Brexit opponents had treated the public with contempt and criticized some Brexit-supporting lawmakers in Prime Minister Theresa May’s Conservative Party for being “useful idiots” for the Remain campaign.