Police recorded a total of 260 cases of alleged electoral fraud in 2016, with convictions for a Tory councillor who gave a false address and a man who voted twice in the European Union referendum.
Analysis by the Electoral Commission found six incidents where people accepted cautions, while police were waiting for advice from prosecutors on five cases and 40 allegations remained under investigation by officers.
The report found that there was an increase in the number of people trying to vote while claiming to be someone else, and the commission called for an "accessible" proof of identity scheme to be introduced at polling stations.
The report highlighted the conviction of Richard Smalley, a Tory candidate who was elected to Derby City Council in the May 2016 local elections after submitting a false address.
He pleaded guilty in August 2016 and was sentenced to two months in prison and banned from standing for election for five years.
The other conviction was for a voter who turned up at a polling station in East Ayrshire and used the name of a friend to cast his ballot in the EU referendum.
The man, who was not named in the report, turned up again later and used his own name to get another vote but because he was "very tall and wore distinctive clothing" suspicions were raised that he had already passed through the polling station.
He pleaded guilty in court and was handed a 300-hour community payback order, as well as a five-year ban on standing for office.
The data for 2016 showed an increase in the number of allegations of "personation" - purporting to be someone else to cast a vote - up from 21 cases in 2014 and 26 in 2015 to 44 in 2016.
The commission has recommended that "a proof of identity scheme should be developed and implemented for polling station voters in Great Britain.
"This would address the current absence of effective checks against personation and improve public confidence," the report said.
Ailsa Irvine, director of electoral administration and guidance at the Electoral Commission, said: "It is important that voters are confident that the police and prosecuting authorities take allegations of electoral fraud seriously.
"The findings from our report show that significant sentences will be imposed when electoral law is broken, and that those responsible for electoral fraud can face jail.
"Voters should be confident that they can report any concerns about electoral fraud. Anyone who has evidence that an electoral offence has been committed should contact the police immediately or report it anonymously through the Crimestoppers website or 0800 555 111."
A Cabinet Office spokeswoman said: "This government is focused on protecting the right of everyone to have their say and participate in our democracy.
"That is why we recently announced new measures on the back of Sir Eric Pickles' report to combat electoral fraud and protect anyone who is at risk of being bullied, undermined or tricked out of their vote - and their democratic right.
"Through these measures we are ensuring the integrity of our electoral system while building a clear and secure democracy that works for everyone."