Zimbabwe’s main opposition leader Morgan Tsvangirai is reportedly fighting for his life in hospital.

The 65-year-old is critically ill in South Africa, where he has been receiving treatment for colon cancer.

His supporters should “brace for the worst”, a source told Reuters news agency.

“From the medical report that I received yesterday the situation is not looking good,” the source said.

Mr Tsvangirai, who founded Zimbabwe’s Movement for Democratic Change (MDC) party, has been a key figure in opposing the country’s ousted former president Robert Mugabe.

Speaking last year, he claimed he had survived a number of assassination attempts and had been subjected to brutal beatings over the years.

His wife Susan was killed in a car crash in 2009, in which he suffered non-life threatening injuries.