Information about the highest risk countries is best built up from a number of sources. The US State Department issues around five travel warnings a month, while the UK Foreign Office has a colour-coded warnings guide.

Somalia is a country with high levels of internal insecurity in which westerners are targeted. Two aid workers – a Kenyan and a Briton – were abducted in May and then released a week later. Last year a journalist and a nurse and her escort were shot dead. Suicide-bombers and car-bombs have also featured in the past year.