In England there has been a steady development towards teaching as a Masters level profession; despite fluctuations as eccentric policy makers strut and fret their hour upon the stage. Most teachers gain some Masters level credits during their initial training and, despite inconsistent funding, ambitious teachers complete a full Masters award by part-time study later in their career. These Masters programmes generally develop teachers as practitioner researchers, critically engaging with theory and research evidence to support their workplace enquiries. This approach has a long history in England, building on the work of Lawrence Stenhouse in the 1970s. However, in some ways it clashes with views of good teaching as 'commonsense' and demands for sharing of 'good practice' between schools. Such tension, in the value placed on different kinds of teacher knowledge and learning, exists within a pernicious policy framework of high stakes external quality assurance and accountability for grade based student achievement targets. This research uses focus groups and a survey to investigate the perspectives of teachers in England who have gained a Masters award. It asks to what extent this advanced training has developed teachers' mastery of enquiry and empowered them as change agents, able to promote research-informed practice.