People in English and maths teacher jobs know the benefit of time and consistency when guiding children through a syllabus. 

They may not be surprised to hear that two new reports have found an increasing use of supply teachers is affecting pupils' learning and an over-reliance on temporary cover when teachers are absent is resultingin children being tasked with work that is not demanding enough.

The claims come from the Wales Audit Office and watchdog Estyn and the groups believe that it is secondary school pupils who are the most affected by teacher absence.

A lack of continuity in teaching is magnified in Wales where nearly ten per cent of lessons are currently being covered by supply teachers and on average, each teacher in Wales is absent for seven days a year, compared to 4.5 days in England.

If the absence levels in Wales could be brought in line with England, it is estimated Welsh schools could cut the number of days requiring cover by around 60,000, which would save more than £9 million a year in the cost of teacher cover.

Estyn states: "Supply staff who do not normally work at the school do not know the needs of the learners as well as their usual classroom teachers and the work set is often too undemanding and does not engage learners."

A spokesperson for the Welsh government said the reviews were carried out so authorities could have a clear idea of the impact that teacher absence has on pupils and classrooms.

Shadow minister for education Angela Burns said: "Over-burdened with red tape, demoralised, stressed and dealing with ever-moving goalposts, our teachers are not being allowed to do the very thing we need them to do - teach.

"It is these staff who know what's best for our children and these staff who should be allowed to work with them freely - and permanently."