Using complexity theory to analyse the organisational response to resurgent tuberculosis across London

► Applies complexity theory to a complex and emergent healthcare phenomenon - resurgent tuberculosis in London. ► Takes a clear organisational and inter-organisational perspective on complexity theory in healthcare. ► Finds complexity theory offers a useful but partial framework for analysing the organisational response to the TB epidemic. ► Complexity theory is more robust when informed by macro policy and organisational contexts, such as New Public Management. ► Observes that TB, an ancient disease, still confounds a modern healthcare system.