Around 17 members of the Wolverhampton-based Sling Swing group took part in the choreographed routine with their babies wrapped in slings.
But the celebratory dance almost landed the group in trouble when they were stopped in their tracks by an unimpressed security guard.
Carly Birchell, aged 33, who runs dance classes for mothers and babies in Tettenhall and Penn, said the stunt was intended as a wind-down after the groups audition for this year’s Britain’s Got Talent competition.
“It was just a bit of fun really after the pressure of the audition, but the security guard obviously didn’t see it in that way,” she said. “He just told us we couldn’t dance in Trafalgar Square and said we had to move on.
“He was very polite and looked a little bit embarrassed really.
“Apparently our dance was considered a public demonstration which means we needed prior permission.
“Fortunately it was towards the end of the dance so it didn’t make that much of a difference.”
The incident has since been watched by hundreds of viewers on a Youtube video, which includes the party pooper’s interruption.
Earlier in the day the slinging swingers performed for executive producers at the BGT auditions at The Kennington Oval, after catching the early morning train down from Wolverhampton.
The music and vocal teacher said she was inspired to apply for the talent contest after a flash mob performed by the group in Wolverhampton City Centre got lots of positive comments.
Mrs Birchell, who is mother to 16-month-old Noah, said: “So many people said good things about it. So I thought, let’s go for Britain’s Got Talent.
“I mentioned it to the rest of the group and they were really up for it.”
Their routine, which featured Sway by Michael Buble and Let’s Get Ready to Rhumble by the show’s presenters Ant and Dec, clearly impressed the judges who rubber stamped their passage into the next round of auditions.