UKIP officials have claimed that they missed out on two extra seats in the European Parliament because voters were confused by a party with a similar name.
"An Independence From Europe", a tiny Eurosceptic party formed by former UKIP members, won 23,000 votes in South West England despite having almost no media presence. But this was enough to stop UKIP winning an extra MEP.
A similar scenario happened in South East England. In both regions the Green Party instead took the final MEP seat.
Nigel Farage's party insists that An Independence From Europe, which ran under the slogan "UK Independence Now", chose its name in a bid to deliberately confuse voters by ensuring it appeared at the top of ballot papers, which are arranged alphabetically.
UKIP says that as a result tens of thousands of would-be UKIP voters accidentally voted for the wrong party.
"The name was designed to confuse and it has confused. The Electoral Commission has failed in its principle duty of ensuring that the election is fair," UKIP deputy chairman and disgraced former Conservative MP Neil Hamilton told BuzzFeed.
An Independence From Europe received over 230,000 votes nationwide, equivalent to 1.5% of the total.
An Independence From Europe appeared at the top of most ballot papers, while UKIP were at the bottom.
Jack Duffin, chairman of UKIP's youth wing, claimed 300 ballots were spoilt in the London borough of Hillingdon by voters who mistakenly voted for An Independence From Europe, scribbled it out, then tried to vote again for UKIP.
"Members all over the county have been phoning in over this," he said. "Just standing outside the polling station and there were a lot of people coming out and saying 'I voted for you, top of the ballot'."
"There's been a lot of spoilt ballot papers from people who have gone for the top party, realised their mistake, scribbled it out and gone for UKIP. But it's still spoilt."
However this claim is doubt because Electoral Commission guidelines state that votes should still be counted in similar instances if a voter's intention is clear.
Last month An Independence From Europe's leader told BuzzFeed that his party's name was not an attempt to get to the top of the ballot but was instead a tribute to his Dutch colleagues in the European Parliament.
"I actually chose 'An Independence From Europe' because I've been trying to make friends with people from Holland – and 'An' also means Anglo-Netherlands," said Mike Nattrass.
"I suppose I could have gone for 'Aardvark Party' and yes, it is obvious that it comes near the top of the list. I understand that UKIP are angry but they have no rights to the word 'Independence' and I legally registered it with the Electoral Commission a long time ago."
The row has echoes of the time that a party named the "Literal Democrats" won 10,000 votes in the 1994 European Parliament election, ensuring the Liberal Democrats missed out on an MEP in Devon and East Plymouth.
The UKIP candidate who missed out in South West England was former party press officer Gawain Towler and Donna Edmunds in South East England.
UPDATE: BuzzFeed had a chat with Mike Nattrass, who said people were not voting for his party by mistake and UKIP's claims were misplaced.
"Oh good I'm pleased someone's furious with me – what's wrong with these people. What a load of bollocks. Rubbish," he said.
"I was getting votes for people who didn't want to vote for Nigel Farage. It was fairly obvious what we're standing for, we're to the left of UKIP."
The An Independence From Europe leader did admit that he was still angry at Nigel Farage, who deselected Nattrass as a UKIP MEP.
"I built Euroscepticism in the West Midlands with my money and my time. And once it gets going Nigel only wants people that don't argue with him, people that he can influence. They [deselected me] in spite to get rid of me. He just wants people he can dominate."
But Nattrass denied choosing a party name in a deliberate attempt to top the alphabetically-arranged ballot but joked about about potential future names.
"Aadvarks Never Killed Anybody – we'll do that next time, you and me."
"Most of [An Independence From Europe's candidates] want to keep going – I think they're probably demented but let's keep going, let's so we can do next. I'll probably want someone else to do most of the work for me, probably take it over."
"There was no money from anyone else. I haven't been funded by anyone else, these people [who think otherwise] are from planet Zog. It was fun. It was excellent fun."
"Nigel's so vain he thinks independence is all about him. But I haven't finished yet – I'm going to give him a kicking on the way back in."