Few predicted the explosion in the number of teaching assistants that began two decades ago. But it has had a dramatic and lasting effect on the school workforce, and on schools’ budgets.

Between 1997 and 2010, the number of teachers rose by 12 per cent - but teaching assistants more than tripled (from 60,000 to more 190,000). And an analysis for Tes by the Institute for Fiscal Studies shows how the army of TAs continued to expand even after school funding started to dry up.

But was this the right area of education for government and schools to invest in?

On paper, the evidence basis for teaching assistants is mixed. A major 2009 study by the UCL Institute of Education found that primary and secondary pupils supported by teaching assistants actually made less progress than those of similar ability, class and gender who did not get such assistance.

It found that TAs usually worked with pupils who needed the most help - but this meant that the children spent less time being taught by a qualified teacher.

However, the latest annual report from the Education Endowment Foundation (EEF) suggests that newer research will show that teaching assistants are now having a greater impact on pupils’ learning.

According to one former Treasury official, the level of spending on TAs in the mid to late 2000s created divisions at the very top of government that continue to this day.

“Research started coming out 2005, 06, 07 onwards that said, ‘This is a complete waste of time.’ The Treasury turned violently against teaching assistants from at least 2005-06, even when the Department for Education and Skills was still pumping out [initiatives supporting TAs]. In the last 10 years, if you ask anyone in the Treasury what should we do about school funding, they’d say, ‘Get rid of teaching assistants.’”

A grand plan

Education support staff have swallowed up an increasing share of school spending, the IFS figures show, growing from 11 per cent of maintained primary school budgets in 2002-03 to 18 per cent in 2016-17.

“These figures imply that primaries continued to increase their reliance on TAs, even after funding began to be squeezed from 2010 onwards,” says Luke Sibieta, the IFS programme director who carried out the analysis.

At the same time, teacher costs have fallen from 58 per cent to less than half (45 per cent) of overall primary school spending. Secondary schools have seen a similar trend.

The growth in TAs began in the midst of the last teacher recruitment crisis, as part of a grand plan designed to reduce teacher workload. A government consultation in 2002, Developing the Role of School Support Staff, called for a “revolution in both the nature and the extent of the contribution made by our support staff in school”.

“We shall see support staff numbers continue to grow dramatically - we estimate at least by 50,000 during this Parliament alone,” the report stated.

But, between 2000 and 2010, the number of TAs grew far beyond that - from 80,000 in 2000 to 190,000, while the number of other non-teaching staff grew from 80,000 to 170,000. Teacher numbers increased to a smaller extent during that period, from 400,000 to 450,000.

Today, with schools looking at cutbacks such as reducing the range of subject choices because of a lack of funding for teachers, the former Treasury official suggests they could free up resources by cutting TAs.

And this appears to be exactly what many schools are doing. “Teaching assistants have been first in the firing line over the last few years, because you can have a class that hasn’t got a teaching assistant in it, but you can’t have a class that hasn’t got a teacher in it,” says Andrew Morris, assistant general secretary of the NEU teaching union.

But he sees this as a worrying trend. “Teaching assistants have been proven to be a very effective intervention…There are some children who definitely need their own dedicated teaching assistant because of their individual needs, and others who benefit from a general provision of TAs in the classroom.”

And if TAs do bear the brunt of cuts, it is likely to be poorer pupils who are disproportionately affected. These staff are often funded from the pupil premium in an attempt to close the pervasive attainment gap between disadvantaged pupils and their more affluent classmates.

‘A lot of poor practice’

The IFS data suggests that primary schools spent a “good deal” of their premium money between 2011 and 2016 on employing extra TAs, says Sibieta. But the jury is still out on whether this spending has delivered what it was supposed to achieve in individual schools, he adds. “Evidence suggests that these extra TAs could have helped reduce the attainment gap if they were deployed in effective ways - eg, delivering structured one-to-one interventions - but there is unfortunately still quite a lot of poor practice out there, too.”

Would the money have been better spent in more recent years on ensuring that teacher salaries remained competitive? Although teacher salaries grew under New Labour, they were frozen in 2011 for two years, before being subject to the 1 per cent public sector pay cap that has yet to be lifted for teachers.

Given that pay is cited as a major reason for the current recruitment crisis, has the focus been on the wrong section of the school workforce - at the expense of those who make the biggest impact on pupil attainment?

This is too simplistic, says Valentine Mulholland, head of policy at the NAHT heads’ union. She points out that support staff help to reduce teacher workload - an important factor when it comes to retention.

“Teachers are having to work 50 hours a week already. And I think we need to be clear; support staff are not sitting there twiddling their thumbs,” she says.

The growth of TAs has certainly allowed the role of teachers to evolve. An agreement signed in 2003 by the government and several unions - with the notable exception of the NUT - listed 25 tasks that teachers should be able to delegate to support staff, including putting up classroom displays and routine administrative jobs such as photocopying. The list was scrapped in 2014 under former education secretary Michael Gove, although the principles behind the agreement remain in many schools.

While TAs account for the biggest increase in school spending during the boom years, and the evidence of their effectiveness is mixed, cutting their numbers now is no easy option - it would have a major impact on teachers as well as the TAs who lose their jobs.

@CharlotteSantry