The visit will have an environmental theme, Clarence House said

A Clarence House spokeswoman said the trip "will reinforce Britain's ties with the important Commonwealth countries" in the West Indies.

The royal couple plan to visit Tobago, St Lucia, Jamaica and the UK Overseas Territory of Montserrat.

The themes of the visit will be sustainable development, environmental protection and youth opportunity.

Charles and Camilla will visit a range of projects, ranging from initiatives to protect marine wildlife and conserve historic buildings to schemes aimed at encouraging entrepreneurship and tackling crime.

Rainforest visit

They began their tour in Trinidad, where a guard of honour was formed by dozens of sailors from the Trinidad and Tobago Defence Force Coastguard.

The couple were treated to a performance by the popular calypso singer Denyse Plummer, who told them: "Welcome to Trinidad, the land of steel band, calypso, carnival. A land where you find happy people of every creed and race."

Later, Charles and Camilla are due to travel into the heart of the country's rainforest to visit the Asa Wright nature centre.

Prince Charles is to launch a climate change documentary aimed at raising public awareness about the threat to the Caribbean.

The luxury yacht Leander has been leased from a British businessman.

Later he will be shown a mock crime scene to learn how officers from the Trinidad and Tobago Police Service are putting into practice forensic skills learnt from a new training academy.

Clarence House says that in keeping with the tour's environmental theme the royal couple will travel around the Caribbean on a luxury yacht, the Leander.

Using the 246ft-long vessel to travel between the islands rather than a plane is expected to "significantly" reduce climate change pollutants.

The cost of the Leander, which has a crew of 24, will also be cheaper than travelling by chartered planes, Clarence House said.