THE Travel Advice Unit (071-270 4129) of the Foreign Office is warning travellers to Burma (Myanmar) to keep to 'officially designated tourist areas'. Tourists are 'not allowed access to large parts of the country where there are actual or potential security problems, and no attempt should be made to go to such areas. Overland entry is only permitted through Tachilek in Thailand. Many travellers avoid using the internal air service because of its poor record.'