Voters in last year's parliamentary by-elections lodged complaints about aggressive campaigning tactics, fights between rival supporters, and bizarre activities on polling day, new data shows.
In one case, a voter complained that wealthy party donors were luring young activists to a key seat with the "unfair" promise of free curry, nightclub entertainment and hotel stays.
Others, in letters of complaint to police forces and local authorities, accused politicians of "fly-posting", while detectives were called when scraps broke out over conflicting "political views".
The details, released to the Press Association under the Freedom of Information Act, refer to the parliamentary by-elections in Clacton, Heywood and Middleton, Newark, Rochester and Strood, and Wythenshawe and Sale East.
One eagle-eyed viewer watching the live coverage of the Rochester and Strood by-election, won by Ukip's Tory defector Mark Reckless, was perturbed to see a person "moving about among the tables and taking items" - something the viewer deemed "suspicious", so reported it to Kent Police.
The same by-election saw six complaints made to Medway Council, one of which was about the apparent unsuitability of a candidate, as well as the length of time it took to count the votes and announce the result.
According to Greater Manchester Police (GMP) - whose force area included both the Wythenshawe and Sale East and Heywood and Middleton constituencies - one party organiser found their car was damaged while out delivering leaflets.
In another case, a campaigner was attacked by members of the National Front far-right group following a political discussion which escalated to violence.
Ukip activists in Newark drew a couple of complaints for fixing party posters to street furniture. The anti-Europe party later came second to the Conservative candidate Robert Jenrick.
A resident also contacted the vote's returning officer - who oversees the election - to complain they had been approached by an unnamed party activist in the polling station as they went to cast their ballot paper.
And another complained that Tory donors allegedly supplied junior members with food and lodgings in exchange for hitting the campaign trail. The complainant said: "I feel sure other candidates in this election must have felt that this was completely unfair."
GMP also reported how local election campaigns - which coincided with a parliamentary by-election - saw a complaint made about a defamatory party leaflet, while another prospective candidate in Wigan apparently "caused people in the street to sign a nomination paper to allow them to stand in the next elections" - despite those signing the document believing it to simply confirm their status as local residents.
According to separate figures from the Electoral Commission, 29 million votes were cast at polls held in the UK last year.
This included local elections, European Parliament elections and elections for directly elected mayors across the UK as well as parliamentary and police and crime commissioner by-elections and the Scottish independence referendum.
UK police forces recorded and investigated a total of 272 cases of alleged electoral fraud during that time, of which four resulted in court proceedings.
One of these cases resulted in a conviction after an individual had stolen campaign signs promoting both the Labour and Conservative parties in the Leeds area.
An Electoral Commission spokesman said: "The figures show that proven cases of electoral fraud remain rare, but it is important that no one underestimates how serious it is when it does occur.
"Electoral fraud can refer to many offences, from impersonating a voter at a polling station to making a false statement on nomination papers to become a candidate.
"We have long known that, when fraud is committed, candidates and campaigners are the most likely offenders and voters are the victims.
"Although there are clear plans in place to prevent and detect fraud ahead of the elections in May, there is also a challenge to campaigners.
"They must ensure their behaviour builds trust with all voters, and all those involved in elections must make it a priority to communicate what is and what is not acceptable behaviour at election time."
Assistant Chief Constable Gary Cann of West Midlands Police, the national policing lead for electoral fraud , said : "A statement about someone's character is different to a statement about their political views.
"A comment about a candidate's politics is probably fair game, but to call someone a bigot or a terrorist or an extremist, for example, is different. It can get very unpleasant."
:: Anyone concerned about electoral fraud is asked to contact the Electoral Commission or Crimestoppers.