The territory now known as Yemen has loomed large in British consciousness since Victorian times when Britain ran the area around the port of Aden.The capital is Sanaa.
The UK-Yemeni relationship dates back to 1839, when the strategically crucial southern port was conquered by the British East India Company.
It was ruled as part of British India, until it was made a Crown colony in 1937.
Pressure for the British to leave South Yemen grew in the early 1960s and following a bloody few years of protests, attacks and civil war between royalists and republicans they were driven from Aden in 1967.
The North Yemen Republic and the People's Democratic Republic of Yemen (South Yemen) were then formed, but years of fighting ensued before unification in 1990. However division, conflict and corruption remained and still does.
The early links with Britain had led to Yemeni immigrants forming some of the oldest Muslim communities in the UK - particularly in the port areas of Liverpool, South Shields and Cardiff.
With Aden being the main refuelling stop for ships between Britain and the Far East, many of the seamen went to the UK to work and then settled.
Surely intelligence agencies would have been paying attention to Yemen following the attack of the USS Cole (navy destroyer) in the port of Aden on 12 October 2000.