More than 800,000 voters are being denied a real choice in the May local elections, according to new analysis by the Electoral Reform Society.
The research shows there are 300 council seats in England that have been guaranteed for one party or individual.
This includes 148 seats where candidates are running uncontested, and 152 seats where there is insufficient competition to make the ward fully competitive.
Darren Hughes, chief executive of the Electoral Reform Society, said: ‘Around 850,000 potential voters in England live in wards where a party or individual is guaranteed a seat – weeks before polling day.
‘Large parts of England are at risk of becoming "democracy deserts". This research also highlights ‘under-contested’ seats in multi-member wards, where representation is guaranteed due to a lack of competition. The result is councillors who have no proper mandate from the people they serve.
'This lack of democratic competition is bad for scrutiny, bad for local services and bad for democracy.’
