The show WILL go on: Crocked Spice Emma to perform 'with or without' crutches at London gigs

Baby Spice took a tumble on stage, spraining her ankle, at the girls' Las Vegas show during the last of their U.S. dates earlier this week.

Her injury was unknown to fans until she was photographed hobbling on crutches on Wednesday night at the unveiling of a Virgin Atlantic plane named 'Spice One' in their honour, at Los Angeles International Airport.

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Despite her vow to be on stage at their first London gig, the group have cancelled their pre-recorded performance on Strictly Come Dancing on the Sunday semi-final show.

The band were expected to sing their hit 2 Become 1 in the taping tomorrow, but have decided to let Emma rest her ankle.

After the unveiling of 'Spice One', the girls boarded the plane for a long flight to London Heathrow, where they were greeted by the British media and fans.

The Spice Girls joined TV presenter Vernon Kaye at the official launch of Virgin Atlantic's new terminal at London's Heathrow Airport.

On the flight, the girls had changed into colourful dresses following their sombre, black outfits in Los Angeles hours earlier.

Emma told expectant fans that she was being treated by the same doctor who tended to bandmate Victoria's husband David Beckham's foot injury.

She said: "I'm praying that I will be all right for Saturday.

"Even if I have to come on stage in crutches I'll be there."

Bandmate Geri Halliwell downplayed the seriousness of Emma's injury, declaring: "It's not her metatarsal."

Explaining her injury, she admitted: "I had a tumble on stage and unfortunately I have sprained my ankle."

Embarrassingly, this isn't the first time Emma has had problems with her ankle. In June 1997, she broke it after she fell off towering platform shoes while filming for a Turkish TV show.

Victoria promised fans Saturday's concert would eclipse their previous gigs in Canada and the U.S.

She enthused: "It is going to be amazing. We're going to give you the best show you have ever seen."

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Victoria reiterated her claim that the group had decided to reunite solely for their young children.

Posh Spice said: "For us that have children that was the main thing, showing our kids that mummy was a pop star... [I mean] Mummy is a pop star."

The Spice Girls are set to start their UK dates at London's largest indoor arena, the 20,000-seater O2, formerly the Millennium Dome, this Saturday.

"It's fantastic to have a plane named in our honour," said the girls.

"We wish everyone who travels onboard Spice One a great flight."

Sir Richard Branson added: "We are proud to be bringing the Spice Girls back in style for their home-coming tour, and back in time for Christmas, following their triumphant US shows."

Despite cancelling their Strictly Come Dancing performance this week, the girls will instead perform at the BBC talent show's final.

A BBC spokesperson said: "The Spice Girls performance on BBC One's Strictly Come Dancing - due for transmission on Sunday December 16 - has been postponed as Emma Bunton has sprained her ankle badly and will not be able to perform."

It's no surprise the Spice Girls' opted to appear on the hit show, as their own careers have received a boost from Strictly Come Dancing in recent years.

Melanie Brown came second last month in the hit U.S. version of the show, Dancing With The Stars, and in 2006, Baby Spice reached the semi-finals of Strictly Come Dancing with partner Darren Bennett.