Susan Boyle may face an extended stay in The Priory as she battles to overcome exhaustion, a doctor has warned.

The Britain's Got Talent star was admitted to the London clinic on Sunday after her defeat to Diversity in Saturday's final.

The 48-year-old had been expected to be released ahead of the Britain's Got Talent tour, which begins in Birmingham on June 12.

But The Priory's chief medical officer Chris Thompson has now revealed Boyle could require a longer stay at the clinic.

He told the Daily Telegraph: "I cannot talk specifically about Susan Boyle but any admission to a psychiatric hospital for a matter of days is, in my opinion, a failed admission because either it was unnecessary in the first place or the job hasn’t been done fully.”

Boyle is believed to have been left overwhelmed by the media exposure she received on the talent competition.

She became a worldwide hit in the space of just six weeks after her Britain's Got Talent audition was circulated on YouTube.

The Rocky Road of Susan Boyle