Paw show. The series nine winners were dog trainer Jules O'Dwyer and border collie Matisse, thanks to their cute routine which saw Matisse get caught stealing sausages and chased across an obstacle course by Jules, dressed as a policewoman.
The spectacular centrepiece was the proficient pooch walking across a tightrope - except Matisse has a slight fear of heights, so lookalike stunt-double Chase stepped in for that part of the act.
Viewers were barking mad when they found out, with 800 complaints received by Ofcom and 130 by ITV. The broadcasting watchdog (ahem) ruled that the public had been misled.
Producers said: "Jules' act involves a team of dogs and we are sorry this was not made clearer." Voting charges were refunded. Ruff justice was done.
Coming over here, winning our contests (2013)
Brexit's Got Talent, anyone? Series seven audiences were wowed by shadow theatre troupe Attraction, who contorted themselves all the way to the BGT title. Just one problem: they hailed from Hungary.
Some viewers gave this a lukewarm reception, while The Sun wrote: "It makes a mockery of the show's premise if foreign acts enter, let alone win."
However, hirsute svengali Simon Cowell hit back by insisting he was happy to welcome foreign acts: "I see it as a testament to this country. We want everyone to do well, no matter where they're from. It's quite flattering that they fly all this way because they see this as the flagship show." Köszönöm, as they say in Hungary (it means thank you, lingo fans).
Tears before bedtime (2009)
Singing schoolgirl Hollie Steel's semi-final rendition of "Edelweiss" hit headlines when the 10-year-old froze, forgot the lyrics and broke down in tears, asking if she could start again.
She was initially told by hosts Ant and Dec that there wasn't enough time but boss Cowell over-ruled them and let Steel perform again at the end of the show.
It was an uncomfortable moment and Bruce Forsyth was among those who questioned whether children should be allowed to enter such a high-pressure competition: "I don't think that's entertainment. Have a separate show called British Children Have Talent." Cowell dismissed his criticisms, calling Forsyth "Mr Grumpy". Pots and kettles.
Britain's got tassels (2012)
Eyes boggled in series six at the raunchy audition of burlesque dancer Beatrix Von Bourbon. Despite being broadcast at 8.25pm, more than half-an-hour before the watershed, she stripped down to nipple tassels.
Von Bourbon's breasts were covered with superimposed stars but Ofcom still received 70 complaints.
Producers didn't learn their lesson. The following series, Keri Graham's controversial audition involved stripping to her underwear and gyrating on Simon Cowell, while guest performer Jennifer "J-Lo" Lopez's skimpy on-stage costume and raunchy dance routine also attracted complaints.
Meanwhile, 71-year-old Kelly Fox's audition saw her sing a saucy ditty called "Kiss My Ass". During her performance, Cowell planted a smacker on fellow judge Amanda Holden's backside.
One member of the National Association of Headteachers said: "These were scenes which no mum or dad with an ounce of morality would want their child to see." Crikey.
Susan Boyle's spine-tingling series three audition went viral and turned the Scots singer into an overnight global sensation.
"SuBo" is still by far the biggest act the show has discovered, having sold five times more records than any other BGT performer - although what many forget is that she didn't actually win, getting beaten into second place by streetdance posse Diversity.
By the time she went through to the live shows, producers were accused of exploiting a vulnerable woman, with report suggesting Boyle was struggling to cope with her new-found fame.
The Press Complaints Commission became concerned by tabloid stories about her erratic behaviour and speculation about her mental health, writing to remind editors about privacy laws.
The morning after the final, Boyle was admitted to private psychiatric clinic The Priory, with producers saying she was "exhausted and emotionally drained". Even PM Gordon Brown wished her well.
Simon Cowell later admitted: "Looking back, it has become clear to me that we didn't handle the situation with Susan as well as we could have."
Series one contestant Richard Bates - a novelty organist, ironically enough - claimed he quit the show due to a hand injury.
In fact, Lancashire Police had contacted producers to inform them that he was listed on the sex offender's register for an indecent assault on a boy two years previously.
Police expressed concern that the victim might see Bates on TV, so he was disqualified.
It was quite a series for criminal controversy. Drag dance troupe Kit-Kat Dolls were also ejected from the contest, after tabloids revealed that three of the nine members were escorts. Which was nice.
Not on your Kelly (2009)
Kelly Brook. Photo / Getty Images
Series three unveiled a fourth judge on the panel: actress, model and former Big Breakfast flop Kelly Brook. After just six days of filming, though, it was announced that she had been axed.
Embarrassed producers claimed that the format was "too complicated" with four judges. Brook was credited as a "guest judge" for auditions filmed during her six-day stint.
Rumours swirled that audiences hadn't warmed to her, and that hosts Ant and Dec weren't keen on Kelly either.
Brook later claimed she was "relieved" to have been sacked. Two series later, a fourth judge was added after all. Awkward.
Untrained melody (2007)
Not to be confused with Cambodian tyrant Pol Pot, snaggle-toothed tenor Paul Potts was BGT's first ever winner - but faced allegations that rather than being a rags-to-riches discovery, he was an established performer who had trained under Luciano Pavarotti.
Potts denied this, insisting he had only appeared in amateur operas and had a single lesson with Pavarotti.
Similar controversy followed in series two, when all-girl string quartet Scala - now called Escala - attracted tabloid flak for being professional musicians who'd been the string section for pop group McFly's arena tour and who were invited to audition by Simon Cowell after playing at an X Factor wrap party.
New kid on the blog (2011)
Parke life! During the series five semi-finals, an anonymous blog - claimed to be written by an executive at Cowell's company Syco - alleged that the show was fixed for baby-faced, Bieber-haired youngster Ronan Parke to win.
It said that Syco had spent two years grooming the 12-year-old Norfolk singer for stardom and that he was already signed to Sony records.
The allegations were strenuously denied and Cowell even called in police to track down the blogger.
He was eventually cautioned by police and apologised for his actions, while bookies' favourite Parke made it to the final before losing out to the deeply forgettable Jai McDowall.
We're going to need a bigger vote (2008)
Back in series two, BGT bosses were accused of fixing the result by manipulating the viewers' vote. In all five live semi-finals, the act performing last won the public poll and progressed to the final.
A spokesperson said this was "nothing more than a coincidence... The judges have no say over the running order." The pattern even continued for the first three semi-finals of the following series before it was broken.
There was further controversy in series six, when the new BGT mobile app caused chaos. Thousands of fans spent £1.49 buying three votes to save their favourite acts but a technical glitch during the first semi-final meant that more than half of votes failed to register. The app was abandoned for the rest of the series and Ofcom ruled that ITV was at fault.
Talk about walking on eggshells. In the series seven final, during the performance by singing Welsh siblings Richard & Adam, a woman stormed the stage and started pelting Simon Cowell with eggs.
Some viewers watched in horror. Others cheered her on. One missile struck its target and Cowell had to remove his yolk-splattered jacket for the remainder of the show.
The stage invader was soon identified as viola player Natalie Holt, who had been rejected the previous year with her classical group RaVen Quartet.
She released a statement criticising Cowell's influence on the music industry. Judge Amanda Holden helpfully called Holt a "stupid cow". The eggs were unavailable for comment.
