Madonna's husband Guy Ritchie is pulling out all the stops for the Material Girl's 50th birthday bash this week. He has secretly commissioned a  new work by urban graffiti artist Banksy . Just what the tagger comes up with is anyone's guess . No doubt a work of stunning originality and imagination . Well, there's a first time for everything . Madonna will be thrilled I'm sure

small bronze sparrow which was part of a Tracey Emin sculpture which had gone missing from its home in Liverpool has been returned.

An anonymous caller left a message on BBC Radio Merseyside's answerphone, saying they had left the £60,000 artwork in the grounds of The Oratory.

The bird was found in an envelope marked "FAO Tracey Emin: URGENT!"

A note inside read: "We are sorry - No harm meant. We would have returned it sooner but we were scared xxx."

The local BBC station discovered the disappearance of the bird earlier this week and contacted the police.

Tracey Emin said it was "a crime and an insult to Liverpool."

The artwork, The Roman Standard, which features the 10cm (4in) sparrow on a 4m (13ft) pole, was commissioned by the BBC for the art05 festival three years ago. Emin's work in general is pretty appalling but this sculpture looks quite nice. Must have been made by someone else

The latest work by controversial artist Banksy is a mural ‘One Nation Under CCTV’ painted next to a CCTV camera at a Post Office yard in the West End of London. Banksy said”We could have put prints up for sale and made a fortune, but that’s not what this is about. We wanted people to be able to come here and have a go themselves. We did a show where we gave away free canvases to kids a couple of years ago, and this is just a progression from that. We’re giving away a piece of wall instead of the canvas.’

French graffiti legend Blek le Rat is set to appear . Banksy is a huge fan. ‘Every time I think I’ve painted something slightly original, I find out that Blek le Rat has done it, too,’ he says, ‘only Blek did it 20 years earlier.’

Described as Britain’s Andy Warhol, undercover graffiti guerrilla Banksy is not only our most important working artist, but one of the world’s most elusive criminals.

In January, a wall defaced by his spray can sold for £208,100. Everyone from Jude Law to Brangelina has his politically charged stencils on their walls

An abstract portrait by Pablo Picasso on Wednesday smashed the record for an artwork sold in Australia, netting £3.1 million pounds) at an auction in Sydney.

The 1954 painting "Sylvette", which clearly showed the ponytail and young face of model and later successful artist, Sylvette David, amid bright swathes of red, yellow and green, was sold to an unidentified phone bidder.

"Sydney is the New York of the art market in the southern hemisphere," Deutscher-Menzies Galleries spokeswoman Marie Geissler told Reuters, adding the sale proved Australian galleries could sell works internationally.

The Picasso easily broke the country's previous record of A$3.48 million, paid for a work last year by Brett Whiteley, the late wild-haired bad boy of Australian Art.

Australia has been experiencing a year-long boom in art sales, driven by cashed-up collectors involved in the country's China-driven mining boom.