The rules against people calling themselves an MP usually get a flurry of publicity in the run-up to a general election. Indeed, it’s part of the pre-election “Will it be an internet election this time?” tradition to have a story about how “MPs who use [insert currently fashionable internet tool] face disaster because they’ve called themselves an MP”.

This time round it’s been Twitter, with the story that MPs who have chosen a Twitter username containing “MP” will run into problems as they officially stop being MPs when Parliament is dissolved for a general election. So if they tweet during the campaign as if they were still an MP they would be breaking these rules. (This is different from, for example, local councillors – who continue to legally be councillors until several days after the election.)

There are three other regular parts of this tradition. First, the danger usually gets talked up at the expense of a cool look at the actual risks. In the case of Twitter, they are pretty minimal because you can change your name and back again (as I did).

Second, the Parliamentary authorities tend to get a bad rap. Although in other respects (Parliamentary footage on YouTube anyone?) Parliament hasn’t moved with the internet times, the rules about what MPs can do with websites, email addresses and the like have been regularly and sensibly updated ahead of each of the last few general elections.

But thirdly, there’s almost never any detail on exactly which rules an MP would be breaking. You can’t call yourself an MP if you’re not one. But what happens if you do?

In fact there isn’t a “You must be an MP to call yourself an MP” law. Parliament does make rules, however, for the conduct of its own members and for the protection of Parliamentary privilege.

These say that you can’t call yourself an MP if you aren’t one, with the possibility of the Committee on Standards and Privileges taking action if you break this rule.

For non-MPs, there is still the possibility of punishment as breaking the rules about calling yourself an MP could be judged a breach of Parliamentary privilege. Parliament has the power to punish non-MPs for such offences, though it has traditionally used them very cautiously.

There are also two laws under which someone might be prosecuted. First, there is law around fraud. Passing yourself off as an MP could constitute fraud, particularly if you did it in order to help win an election which then brings you a salary (i.e. financial gain).

Second, there is the broad electoral offence of “undue influence” which has been interpreted in some cases to mean cover providing false information to the electorate. It is not easy to pass the legal test for convicting under this offence and rightly so – given the need to protect freedom of speech. In particular, a prosecution would have to prove that identified individuals had been affected by the deceit. Simply saying “Someone said X and it isn’t true” is not enough.

In other words, it’s far from clear exactly what would happen if an MP called themselves an MP in some way. Where there are written instructions from the Parliamentary authorities, it is fair to expect MPs to follow them accurately – which, after all is what the rest of us have to do under many of the rules MPs make. But if someone accidentally stumbles into a minor problem area that isn’t explicitly covered by those instructions, then it makes sense not to get too excited.

Thank you to the House of Commons Information Office for answering a couple of queries from me.