Just one vote

Here is logical / illogical premise.

Only one person needs to vote in a UK parliamentary election to elect an MP. Democratic principle can be exercised by just one person.

Proof:

In any election there is essentially only a winner and a loser, in most election only two candidates are in serious running for the win. Therefore anybody that votes for the also runs need not bother voting.

Which leaves two candidates and their voters. Now if candidate X gets 20,000 votes and candidate y gets 23,200 voters then the net win is 3,200. So in fact the forty thousand votes than can be paired in the end don't matter so they can stay at home as well.

Now whether you win by 3,200 or 1 doesn't make any difference you don't get bonus points. So really 3,199 voters might as well save their legs as well.

Just one person needs to go out and vote to elect the new member of parliament.

The trick is identifying the one person.