This study aims to establish whether the use of the Flex 19G EBUS-TBNA needle can improve the diagnostic yield of EBUS sampling procedures compared to the use of the conventional TBNA needle, thereby allowing more accurate diagnoses and reducing the need repeat procedures or more invasive surgical biopsies, without causing an increase in complication rates. Patients with enlarged mediastinal and hilar lymph nodes referred for EBUS-TBNA will be randomised to have their nodes sampled by either the EBUS-TBNA needle (conventional procedure) or the novel Flex 19G EBUS-TBNA needle. The investigators hope to recruit 250 patients over a 24 month period.