The term 'payroll vote' has traditionally been used to describe MPs who hold positions from which they would have to resign in order to oppose the government. This includes paid and unpaid positions.
The term can also include roles which do not formally bind MPs to vote with the government, but may have been given out by the prime minister in order to reward or encourage loyalty. This is the wider payroll vote.
Ministers and parliamentary private secretaries comprise the traditional payroll vote. They are restricted from voting against the government or even "associating themselves with recommendations critical of or embarrassing to the government" by the Ministerial Code.
The ‘wider payroll vote’ is a relatively new phenomenon. It is comprised of the traditional payroll vote, as well as the prime minister’s trade envoys and Conservative Party vice-chairs.
Trade envoys are an unsalaried group of parliamentarians who work to promote the United Kingdom’s trade interests in specific markets. Though they are a cross-party network, 12 of the 15 trade envoys in the House of Commons at present are Conservatives.
Vice-chairs are MPs given a specific subject area to represent within the internal organisation of the Conservative Party. All vice-chairs are paid a salary in addition to their MP salary.
Trade envoys are appointed by the prime minister, with Conservative prime ministers also appointing party vice-chairs. Neither position is technically bound to support the government – however, some MPs have chosen to resign from these positions in order to oppose the government over issues of policy. Maria Caulfield MP, Ben Bradley MP and Rehman Chishti MP all did so to oppose prime minister Theresa May over Brexit in 2018.
This is not an obligation though: in November 2018, Ranil Jayawardena MP resigned as parliamentary private secretary to the Ministry of Justice’s ministerial team to vote against the prime minister’s Brexit deal, but kept his position as the prime minister’s trade envoy to Sri Lanka.
There are currently 95 ministers who are obliged to vote with the government in the House of Commons. However, the full size of the current traditional payroll vote is unknown, as data on how many parliamentary private secretaries have been appointed under prime minister Boris Johnson has not yet been released.
There are a further 19 MPs in the wider payroll vote: six vice-chairs, two deputy chairs and 12 trade envoys, one of whom is also a deputy chair.
The Ministerial and Other Salaries Act 1975 limited the number of paid government ministers to 109, and the House of Commons Disqualification Act 1975 capped the number of ministers that could sit in the House of Commons at any one time at 95.
The number of parliamentary private secretaries, trade envoys, vice-chairs and other positions that the prime minister can create is entirely unrestricted. Because of the implications this could have for Parliament’s ability to scrutinise government, the Public Administration Select Committee recommended, in 2010, that the payroll vote should be limited to 15% of the membership of the House.
A report written by the same committee the following year recommended that only secretaries of state should be allowed to have parliamentary private secretaries.
There has been a steady increase in the number of MPs who act as ministers and parliamentary private secretaries over the course of the 20th century, from 101 MPs in January 1960 to 141 MPs in November 2018.
An increase in the wider payroll vote was an innovation of Theresa May’s time as prime minister. She oversaw a threefold increase in the number of Conservative MPs in the House of Commons with trade envoy positions, without appointing a single non-Conservative trade envoy. She also appointed a further 10 MPs as vice-chairs in January 2018, in addition to the existing four.
The Public Administration Select Committee has raised questions about the necessity of an increasing payroll vote, given the reduced functions of central government brought about by privatisation and devolution in the years since 1960.
Plans to reduce the number of MPs in Parliament from 650 to 600 in 2022 have renewed concerns about the size of the payroll vote. Some argue that this will lead to the payroll vote taking up a larger proportion of overall MPs, skewing the influence of the government in the House of Commons.