Jeremy Corbyn 2016,
"He said the result of the poll means the exit clause – Article 50, which would give a two year period for Britain to leave – must be observed as soon as possible in an interview with the BBC.
“The British people have made their decision. We must respect that result and Article 50 has to be invoked now so that we negotiate an exit from European Union.
“Obviously there has to be strategy but the whole point of the referendum was that the public would be asked their opinion. They’ve given their opinion. It is up for parliament to now act on that opinion. "
https://labourlist.org/2016/06/corbyn-article-50-has-to-be-invoked-now/