How would that work? You need to show valid ID to vote, and it won’t be checked just by Labour partisans.
According to the Electoral Commission, in the whole of the UK, in many elections at every level, there were under 260 election related offences in 2025. Over half were campaigning offences. a number were expense related offences. Under 50 were registration offences, and only 14 were voting offences.
The political parties have a good system of checks and balances on each other when it comes to voting.