Police will not be taking any action over claims of overspending by the Conservative Party at two by-elections.
Channel 4 News said it had obtained hundreds of pages of receipts which suggested the party broke electoral rules in three 2014 by-elections in Newark, Clacton, and Rochester and Strood.
A party spokeswoman said: "All by-election spending has been correctly recorded in accordance with the law."
Campaign spending in by-elections is limited to £100,000 for each party.
Channel 4 News said it had uncovered £56,866.75 of undeclared hotel bills in Rochester and Strood, which would have taken the party £53,659.83 over the £100,000 spending limit.
It found bills totalling £26,786.14 in Clacton, which would have taken the party £10,835.36 over the limit, and bills totalling £10,459.30 in Newark, which would meant a £6,650.28 overspend.
The Tories defeated Ukip in Newark, but went on to lose the other two by-elections that year.
In relation to the claims in Newark, Chris Eyre, the chief constable of Nottinghamshire Police, said it was too late to bring any prosecutions for alleged election expenses offences for the poll which took place on June 5 2014.
In a letter to police and crime commissioner Paddy Tipping, Mr Eyre said there was a 12-month statutory limit in prosecutions brought under the Representation of the People Act, the law which governs elections.
As the financial return for the poll was made on July 4 2014 the limit has passed, he said.
He added: "From the information available no prosecution can be brought in this case."
Kent Police said it will also not be taking any action in relation to the alleged overspend for the Rochester and Strood by-election for the same reason, after taking legal advice.
A spokeswoman for Essex Police said the force had not received any complaints about any alleged breach of electoral law relating to the Clacton poll.
:: In 2014, Conservative candidate Robert Jenrick won the Newark by-election with 7,403 more votes than nearest rival Roger Helmer, for Ukip. Mr Jenrick retained the seat in last year's general election.
Tory defector Douglas Carswell won Clacton in the 2014 by-election for Ukip - becoming the Eurosceptic party's first MP - winning again in 2015.
Another Tory defector, Mark Reckless, took Rochester and Strood for Ukip in 2014, but lost in the 2015 poll to Conservative candidate Kelly Tolhurst.