The Independent Parliamentary Standards Authority (IPSA) regulates and funds MPs’ business costs and expenses. As part of this role, IPSA sets a maximum budget from which MPs can fund their staffing costs. This is based on an average of four full-time-equivalent staff members, although each MP can choose to deploy this budget to suit their own staffing needs.
MPs’ budgets are reviewed each year. In 2012, the staffing budget was increased by 25% for London Area MPs and by 19% for non-London Area MPs, in part to allow MPs to employ more staff to support their work with constituents. In April 2018, the staffing budget will increase by a further 1.8% to allow for staff pay rises.
In addition, MPs may request to increase their budget if they provide evidence of having incurred unforeseen, exceptional costs. Such requests for contingency funding are considered on a case-by-case basis. If any MP finds that their constituency caseload has increased to an unmanageable level as a result of preparations for the UK leaving the EU (or another exceptional issue), they may apply for an increase to their staffing budget in this way.