House of Commons Commission
The House of Commons Commission is the overall supervisory body of the House of Commons Administration. It prepares and lays before the House the Estimates for the House of Commons Service; it decides most matters of policy; and it appoints staff of the House, and determines their pay, pensions and other conditions of service. The House of Commons Commission was established by the House of Commons (Administration) Act 1978, which provides that the Commission should have six members: the Speaker as Chairman; the Leader of the House; a Member of the House nominated by the Leader of the Opposition (normally the Shadow Leader of the House); and three other Members appointed by the House, none of whom may be a Minister. One Member of the Commission acts as its spokesperson in the House (for example in answering Parliamentary Questions).
Further information on this subject can be found from the following link.