People who actually join a political party are likely to care more about politics than the average voter and to be more knowledgeable. In some parties (but not all) they have a strong influence on party policy.
I find it astonishing that Jeremy Corbyn has chosen to ignore the views of the majority of Labour MPs, the majority of Labour Party members and the majority of Labour Party voters, all of whom want to Remain in the EU.
To think that London, or anywhere else for that matter, does not belong to any one demographic
What is a reasonable minimum spend for an online grocery delivery??