Amy Winehouse might have to miss Glastonbury and the Nelson Mandela concert next week, the singer’s spokesman has admitted.

The troubled singer is booked to play at Mandela’s 90th birthday concert in Hyde Park on Friday June 27 followed by Glastonbury, directly before headliner Jay-Z, the following day.

But Winehouse, who has fought heroin and crack addiction, is still in a London clinic awaiting the results of tests following her collapse at home.

A spokesman said Winehouse still intended to perform at both high-profile events, but that that doctors would decide whether she was well enough to take to the stage.

He said: “Amy has undergone more scans and tests and we are awaiting the verdict of her doctors.

“At present, she still intends to perform at the two scheduled dates next week. However, a decision will be made entirely upon the advice of her doctors and in her best interests.”

Winehouse, 24, has been in the London Clinic since being taken there by her father Mitch after fainting at her home in Camden, north London, on Monday.

When a United Nation’s panel released a report criticizing “celebrity ‘endorsement’ of drug-related lifestyles,” they seemed to be talking about Amy Winehouse, a singer in the British tabloids more for her partying than for her songs, although one of them was a screed against rehab.

Over the weekend, another U.N. official stepped up to the plate for a more specific whacking. From an Op-Ed by Antonio Maria Costa, the executive director of the United Nations Office on Drugs and Crime, in The Observer:

Amy Winehouse might adopt a defiant pose and slur her way through ‘Rehab’, but does she realise the message she sends to others who are vulnerable to addiction and who cannot afford expensive treatment? Are such stars who flaunt their drug use aware of the damage caused by the trafficking of cocaine from South America via Africa to Europe? One song, one picture, one quote that makes cocaine look cool can undo millions of pounds’ worth of anti-drug education and prevention.

Why is this behaviour socially acceptable? If Ms Winehouse advertised fur coats or blood diamonds, there would be a backlash, yet when she is the poster girl for drug abuse, nobody seems to care.

But the Winehouse camp was not taking this laying down, as these remarks via CNN showed:

Winehouse’s spokesman, Chris Goodman, called Costa a “ludicrous man.”

“Amy has never given a quote about drugs or flaunted it in any way,” Goodman told the newspaper. “She’s had some problems and is trying to get better. The U.N. should get its own house in order.”

The U.N. might argue that its recent push against celebrities was part of getting its house in order on drug control. Was it a wise move?