Are all parties implicated?

To some extent, yes but so far that have been key differences between the parties. There have been concerns for years that the system is being abused. It is a complicated area of law that is woefully out of date.  Even when there are investigations, such as into Zac Goldsmith’s spending in the 2010 election, a great deal of leeway is given to the interpretation of the rules and the public interest in a prosecution so there are rarely serious consequences.

As Michael Crick has said, “election expenses are among the great works of fiction of British politics.”  

Our map shows the range of MPs and candidates that have had their expenses challenged.  Some have already been exonerated and some complaints may even have been retaliatory - if you question my expenses I’ll question yours. However the problems with our election expenses system are not new, they are not isolated incidents and they do not affect just one party.

The difference with the current scandal is the scale of the abuse and the allegation that this involved strategic decisions by the Conservative Party centrally, rather than just the actions of one candidate or agent. 

Michael Crick has published a detailed analysis of the allegations against the Labour and Conservative parties and he draws attention to the different levels of spending involved:

“These costs are tiny, though, compared to the Conservative effort – almost trivial. The Labour cars cost about £50 each per day. The Conservative Battlebuses cost up to £400.The Labour vehicles had up to six activists each. The Conservative coaches had up to 50. We know the Labour Party spent £282.40 on hotel costs for student activists. We know the Conservatives, in contrast, spent £38,000 on accommodation for their Battlebus volunteers.”

As District Judge Barron said in his decision to extend the deadline for the investigation in South Thanet: 

"In my judgment the combination of circumstances before me is wholly exceptional and goes far beyond the usual circumstances that would exist in a typical case where election offences are being investigated."