Public Health Observatories (PHOs) were created in England in 2000 as an important adjunct to the public health system in the country. The observatories were networked together, which allowed pooling of expertise and rapid dissemination of methods and results. The network grew to include the whole of the UK and Ireland and was a very successful force for change until PHOs were subsumed into the new Government Agency Public Health Organization, Public Health England. This paper describes the lessons learnt from their existence in the public health system in England for fourteen years.