The world is awash with theories over why Guy Ritchie and Madonna are divorcing, but the mass circulation tabloid, The Sun, alleges a horse may be implicated.

In a major report, the newspaper quotes unnamed friends who believe it was Madonna's bone-breaking fall from a horse in 2005 - on her 47th birthday - that was the beginning of the end.

The material girl reportedly felt Ritchie was unsympathetic to her plight and did not show her the love and emotional support over the accident she felt that she deserved.

Later arguments often returned to the accident, which proved to be a turning point in the marriage.

It may well have been behind her decision at a concert this week to dedicate a song to the "emotionally retarded".

"You might know a few people who fall into that category," she told concert-goers. "God knows I do."

Madonna's injuries in the accident included four broken ribs, a broken collar bone, shoulder blade and a finger.