The Born Free Foundation says that it is not in a position to offer volunteer opportunities on its conservation projects.

But the international wildlife charity does encourage people to seek opportunities elsewhere in order to make a contribution to essential and often under-resourced projects.

'Volunteers are such an invaluable asset to the wider wildlife conservation effort', it says.

The foundation suggests that volunteers consider working at the Colobus Trust in Kenya or the Shamwari Game Reserve in South Africa through Worldwide Experience. Or at the Limbe Wildlife Centre in Cameroon, which runs its own volunteer programme.

Its other suggestions are:

Born Free has a Travellers Alert system for travellers to report on animal exploitation around the world.

Its Zoo Check Campaign encourages people to take action against poorly treated captive animals by sending in information and pictures.

The charity says:

"It is vital that the information you send us about your experience includes all the necessary facts and is as detailed as possible. Always remember to include the date and time of visit along with the address of the attraction."