The Local Government Boundary Commission is responsible for recommending fair electoral and boundary arrangements for local authorities in England. In doing this it balances three statutory criteria: within an authority, each councillor should represent a similar number of electors; boundaries should be appropriate, reflecting community ties and identities, and its reviews should be informed by local needs, views and circumstances.
It is not necessary for all councils to have single member wards to ensure councillors represent a similar number of electors. When conducting a review, the Commission first decides on the number of coucillors needed for an authority. It then calculates how many electors there should be per councillor. When doing this, it is required to use as a baseline a forecast of the number of local electors five years after the competition of its reviews. The forecast number is divided by the number of councillors to give a target number of electors per councillor. The target in multi-member wards is multiplied by the number of councillors in that ward so that councillors represent a similar number of electors.