Seb Dance holds up a sign saying during Nigel Farage's speech | European Parliament UKIP complains about Labour MEP’s ‘he’s lying to you’ sign Labour’s Seb Dance pokes fun at Nigel Farage.

The United Kingdom Independence Party on Wednesday lodged a formal complaint with the European Parliament after Labour MEP Seb Dance held up a sign saying "he's lying to you," during a speech by former UKIP leader Nigel Farage.

Dance told the Telegraph he had been admonished by European Parliament administrators, saying: "The usher came over to gently tell me to hold my sign down but I managed to have it up for most of Farage's speech.

"UKIP often use these clips in isolation on social media and I didn't want to give him the chance to use his speech without challenge."

But UKIP's Bill Etheridge didn't see the funny side and lodged a formal complaint. He wrote: "During the debate today regarding the USA border controls, a member of the British Labour party sat behind Nigel Farage MEP during his speech with a sign making a defamatory personal remark.

"The officials failed to remove him until the end of the speech and when I raised the matter it was not treated with sufficient seriousness by the acting chair."

Farage had urged his fellow MEP to invite U.S. President Donald Trump to the European Parliament.

“All of us here say we are democrats. Well, here’s a chance to prove it: Let us invite President Trump to come here to this European Parliament,” Farage said.

Farage said there should be “an open dialogue with the newly elected most powerful man in the world,” adding that MEPs would be “anti-democratic zealots” if they rejected the idea.