The decision of the House of Commons to place limits on the outside interests pursued by MPs has established a clear public expectation that change is on the way.

But although the House has agreed in principle to regulate second jobs more tightly, when it comes to the actual impact of any new rules – on the activities that MPs are permitted to undertake and consequently on public trust in elected members – the detail will be crucial. Important questions remain about how the Commons will choose to define the limits of the second jobs that MPs are allowed to undertake, and the answers will determine whether these reforms have a substantial and wide-ranging impact on MPs’ extra-curricular activities, or a marginal effect on a handful of contracts.

What is essential is that any new rules provide a workable scheme under which MPs can be certain about the permissibility of paid employment, and that the Commons standards system has a clear basis on which to judge potential breaches. It is also vital that new rules are comprehensible to the public, if they are to help improve the reputation of MPs.

This paper sets out the five questions that MPs now need to answer about proposed changes to the rules governing their outside interests.