Parliamentary boundaries in the UK are drawn up by politically neutral boundary commissions. The new rules constrain the commissions more than the old ones did, but also reduce the opportunities in the process for the parties to influence the final report.

The rules, both old and new, prevent the political consequences of proposed boundaries being taken into account. A party will obviously consider political consequences, in deciding what boundaries it would prefer, but its submissions to the boundary commission have to be expressed in terms of factors permitted by the rules such as community ties