No-one would argue against the place of CPD in schools today, but I believe that for many years there has been a lack of coherent processes and management systems guiding it.

This means that many CPD activities may not be as effective as they could be because many schools do not have a clear idea of exactly what works - and what doesn't.

Despite spending £180 million on staff development and training in 2011, the Teacher Development Trust estimated that 37 per cent of English schools have rarely or never evaluated its impact.

If schools don’t have a full picture of the effectiveness of CPD, how can they know where to target their investment in order to help teachers raise attainment?