A proportional voting system for the House of Commons might not in itself tame executive dominance, if 'hung' parliaments resulted in coalitions, i.e. arrangements in which two or more parties participate in government to the extent of the cabinet being made up of MPs from more than one party.

In such cases cabinet collective responsibility applies, and the minor parties in the coalition become compromised and will not hold government to account.

From the point of view of a healthy democracy, a much more satisfactory arrangement is one in which one party governs with the consent of others. The party or parties deemed to be 'holding the balance' of power do a limited deal with the government over the legislative programme, but reserve the right to oppose measures which are not part of the deal, and do not provide ministers. These parties should feel no inhibition in holding government to account.

The trouble is that it is human nature to want power. What would persuade a party holding the balance not to demand a place in government? Only if people demanded it as the price for their votes. A new kind of party (q.v.) is needed.