Hurricane Ivan was one of the worst storms ever to hit Grenada

HMS Richmond, which took the prime minister of Grenada aboard and aided stranded locals there, is expected to reach the island by Sunday.

Hurricane Ivan has swept through the Caribbean, killing at least 20 people, and is expected to approach Jamaica by Friday evening.

HMS Richmond's commanding officer said they would position the ship "wisely".

The ship's commanding officer Mike McCartain told BBC Radio Five Live he aimed to arrive by late on Sunday afternoon, and would be travelling at a speed of almost 30 knots.

"We'll be chasing (the hurricane) ostensibly up to the north west across the Caribbean Sea so we shouldn't be too affected by it," he said.

At least ten deaths were reported in Grenada earlier this week, where the capital St George's was hit by 145mph (230 km/h) winds.

Grenada's Prime Minister, Keith Mitchell, said the island was "90% devastated" by Hurricane Ivan.

A spokesman for the MoD said around 60 sailors from HMS Richmond, which is normally based in Portsmouth, landed in Grenada to help.

I have declared the country a national disaster Keith Mitchell, Grenada's PM UK tourists flee hurricane's path Jamaica braced for Ivan

Most of the damage was inflicted on the island on Tuesday, but downed communications meant it has taken time for the news to filter out.

Mr Mitchell, who spoke to Radio 4's Today programme, said: "We have really taken a tremendous hit in every respect.

"You are talking hundreds of millions of dollars of damage. I have declared the country a national disaster and I have contacted our international friends and indicated that."

He said the island's nutmeg industry will have taken a "tremendous hit".

Mr Mitchell said the capital's 17th Century prison was damaged, enabling several inmates to escape.

Reports from the island suggested looting was widespread and US students in St George's University have armed themselves against looters with knives, sticks and pepper spray.

The storm is forecast to strike Cuba at the weekend and is thought to be the worst to hit the Caribbean in a decade.