More than 20 oil companies, including some of the world's largest are hoping that a week of diplomatic activity will unblock one of the most fiercely contested exploration licensing rounds in recent years. The companies believe Bangladesh, one of the world's poorest countries, may have some of the region's biggest reserves of natural gas. A conservative consensus among diplomats and western experts suggest that Bangladesh may be sitting on reserves of between 30,000bn and 50,000bn cu ft - up to twice the amount in the UK sector of the North Sea.