Tourists are more likely to fall ill in Mexico than any other holiday destination, according to a new survey.

Belgium and Croatia are the countries where visitors are least likely to pick up a holiday bug, says the Holiday WhichNULL survey.

The number of travellers falling sick in Mexico more than doubled from 27% to 58% in the last two years ago, while illness reported among tourists to all destinations has gone up from ten to 12%.

Those on package holidays fared worse than independent travellers, with 15% falling ill compared to nine per cent of those who made their own arrangements.

Holidaymakers who chose packages where food was provided were twice as likely to fall ill as those with room-only or half-board accommodation.

India proved the most dangerous destination for serious illnesses. One in 25 tourists succumbed to malaria or salmonella poisoning.