Watch: Madonna flashes her nipple during Istanbul show

At her age, many singers are settling for a decline into respectable middle age, with a Christmas album or two, a nice line in sweaters and perhaps a charity benefit gig here and there. Not so Madonna, 53.

The Queen of Pop is working hard to keep up her long-held controversial image on her current European tour, proving she can still hit the headlines while packing out stadiums in 28 countries.

Last week, she superimposed a swastika onto the face of Marine le Pen, a right-wing French politician, during her new live show.

Mademoiselle Le Pen fired back with this gloriously bitchy quote: "We understand how old singers who need to get people talking about them go to such extremes.”

Undaunted, Madge caused outrage this weekend in conservative Turkey after deliberately exposing a nipple on stage. The crowd of over 55,000 went wild as she naughtily played with her bra during a performance of the song ‘Human Nature’ before pulling it down to flash her right breast. She followed up by unzipping her trousers and putting her hand down her pants.

The move attracted a flurry of outrage online, with commentators in Turkey and around the world falling over themselves to condemn Madge for her (deliberate) wardrobe malfunction. Most of the criticism was directed not at the inappropriateness of the move in a Muslim country like Turkey, but at Madonna for daring to expose parts of her body now she’s in her fifties.

'Why is Madonna still showing off her t-ts? No, it's not sexy to see a woman who could be my grandma whipping her nipple around,' wrote one onlooker. Even former tabloid editor Piers Morgan, hardly a champion of good taste himself, tweeted “Most embarrassing, cringe-worthy, desperate moment in the history of music?’

Last year Madonna told journalists at a Super Bowl press conference “You don’t have to show your nipples to be interesting, and it doesn’t necessarily mean you’re cutting-edge if you do.” Clearly she’s changed her mind.

What do you think? Is Madonna flashing her boobs on stage shocking, or just something to be expected given her long history of provocative moves? Is getting raunchy when you’re fiftysomething kinda cool, or just gross?