Although not paid other than their salary as an MP, PPSs help the government to track backbench opinion in Parliament. They are subject to some restrictions as outlined in the Ministerial Code of the British government. A PPS can sit on select committees but must avoid "associating themselves with recommendations critical of, or embarrassing to the Government", and must not make statements or ask questions on matters affecting the minister's department. In particular, the PPS in the Department for Communities and Local Government may not participate in planning decisions or in the consideration of planning cases. PPSs are not members of the government, and all efforts are made to avoid these positions being referred to as such. They are instead considered more simply as normal Members. However, their close confidence with ministers does impose obligations on every PPS. The guidelines surrounding the divulging of information to PPSs are rigid. Ministers choose their own PPSs, but they are expected to consult the Chief Whip and must seek the written approval for each candidate from the Prime Minister. Although not on the government payroll, PPSs are expected to act as part of the payroll vote, voting in line with the government on every division, and are regarded as members of the government for purposes of cabinet collective responsibility. Similarly, a PPS must not appear as a representative for any special policies. When on official Departmental business, a PPS receives travel and subsistence allowance paid out of government funds, as with formal members of the government. This makes the PPS the only type of unpaid advisor who receives reimbursement in the course of duty. A PPS may stand in for the minister at an event as a last resort when the minister cannot appear. This can only happen in exceptional circumstances and must be justified by the minister. If this event is overseas, the substitution also requires the Prime Minister's consent. While not technically part of the government, a PPS is still bound to Collective Ministerial Responsibility and therefore must resign if speaking against government policy.
The role in the career of MPs
The role of PPS is seen as a starting point for many MPs who are looking to become ministers themselves. According to Philip W. Buck, a professor of political science at Stanford University: After the leaking of party details in emails associated with Desmond Swayne, PPS to David Cameron, a writer of the Thirsk and MaltonLabour PartyConstituency Blog commented:
