A string of Conservative MPs and officials could be charged before June’s snap poll over allegations of breaching spending limits at the last General Eection.
Some 14 police forces have sent files to the Crown Prosecution Service - which are understood to refer to more than 30 individuals - and decisions on charges are due in late May and early June.
The allegations concern claims that busloads of activists were ferried to marginal seats and put up in hotels at the national party’s expense for the 2015 election, without the costs being listed as “local expenses”.
A Crown Prosecution Service spokesman said that the announcement of the snap general election would have no impact on the timing of decisions on whether to press charges.
The precise deadlines for decisions vary from area to area, depending on the date last year on which the local force secured an extension to its investigations into alleged breaches of election finance laws.
Each file relates to allegations concerning a candidate and an election agent and the number of people involved totals at least 30, a CPS spokesman said.
Allegations highlighted by Channel 4 News and the Daily Mirror relate to busloads of Conservative activists sent to key seats, whose expenses were reported as part of national campaign spend rather than falling within the lower constituency limits.
The CPS declined to say which constituencies are involved, but said files had been received from the Met Police, as well as a long list of other forces.
Ukip leader Paul Nuttall suggested that Theresa May's election announcement may have been motivated in part to avoid "the prospect of a slew of Tory-held by-elections caused by the seeming systematic breach of electoral law at the last election, predominantly in places where Ukip were pressing the Conservatives hard".
A Conservative spokesman said: “We are cooperating with the ongoing investigations.”