Dedicated and hard-working staff at all levels of large healthcare organisations can be frustrated by a perceived inability to influence healthcare priorities. One way of enabling such practitioners to shape and improve services is to bring them together in 'communities of influence'. These are informal groups or networks of committed people who meet regularly to share experiences develop a collective voice and influence policy and practice at local and national levels. Such 'bottom-up' approaches to change can complement the more conventional management mechanisms widely employed today....