The SNP has called on the Metropolitan Police to investigate whether the Conservatives fraudulently recorded local candidate spending as part of their national expenditure.
SNP MP Pete Wishart wrote to the Met Police to call for an investigation into whether the Tories attempted to subvert the Representation of the People Act in the way they recorded their election spending.
"Currently there are some 10 police forces investigating the electoral expenditure of some 28 Conservative candidates who contested the 2015 General Election," he said in a letter disclosed to Channel 4 News.
"Where the ongoing cases will take their legal course, the Conservative Party as a whole must be properly investigated to ascertain if there was any systematic attempt to circumvent electoral legislation defining candidate and national expenditure.
"If evidence is found of wrongdoing I am asking you to submit that evidence to the Director of Public Prosecutions."
Police forces are now investigating whether the Tories breached election spending rules by failing to record accommodation costs for bussing activists to key constituencies.
They are alleged to have recorded the costs as part of national campaign spending, rather than as part of candidates' spending.
Up to 29 Conservative candidates are thought to have benefitted from the Tory "Battlebus" campaigns.
The Conservatives said they failed to register the costs following an investigation by Channel 4, blaming an "administrative error".
