UK critics have been sharply divided about Madonna's West End debut in Up For Grabs at London's Wyndham Theatre - and not just about the pop star's performance.

Madonna plays Loren, an art dealer who needs to sell a Jackson Pollock canvas for $20m (�13.7m) to clear her debts, in David Williamson's satirical comedy about the tough dealing in the New York art world.

As celebrity casting goes, this is the big one

Daily Telegraph

The Guardian was dismissive, describing Madonna as "a dogged trier lacking in technique or mystery - what the audience is applauding is not achievement, but some hollow concept of celebrity".

But, the review went on, Madonna is "buttressed by some strong supporting players", including Sian Thomas and Megan Dodds.

The Express, too, was unimpressed. Under the headline "Madonna falls flat" it described her debut as "frankly, a flop".

"She tries hard but she's as flat as a flounder", said the paper, though the reviewer admitted: "True, you can't take your eyes off her because she's Madonna."

'Seriously nervous'

But other papers were more generous. The Daily Telegraph noted that "as celebrity casting goes, this is the big one" but was guardedly approving.

"For the first 10 minutes she seems seriously nervous," said the paper, but went on: "Her performance is far from the disaster many were predicting and some were maliciously hoping for."

The press was kept out of the preview shows

The paper added: "Madonna is often funny and sometimes touching" and praised supporting cast.

The Times, too said that Madonna's acting "strengthens as the evening progresses".

For the Daily Mail the culprit was the play itself.

"It's a terrible play - and Madonna gets better in direct proportion to the deterioration of her surroundings.

"She is rather magnificent in a raincoat," said the review.

The Mirror noted the "wild applause" and regarded the event as a successful piece of show business.

"Her fans will be in ecstasy seeing their idol so up close and personal," it said.

However, it concluded: "If Madonna's West End debut was anything to go by, the Material Girl will not be giving up her day job."