During the five years of her current headship, SallyAnne Stanton has seen her role develop dramatically.

Today, her influence extends well beyond the bounds of her own school. The headteacher of Southampton’s Kanes Hill primary, she is also co-leader of a successful network of schools in the city, and has been influential in her local authority securing funding to support future collaboration.

Her own school has flourished. When she took over five years ago it was struggling - but it has now been judged by Ofsted to be a “very effective and inclusive school”. Its Year 6 Sats results have improved dramatically and its value-added scores are among the top 3 per cent.

It is the collaboration with other schools which has helped the Kanes Hill recovery.

“It raised my head above the parapet,” she says. “In a school like ours, which is in a socially deprived area, there is challenging behaviour, there are lots of issues.

“You could easily get bogged down in making lots of excuses, like look at where these children come from, look at what they have to cope with.

“But you have to lift yourself above that and say actually, these kids are just as capable as any other children in the country. And the staff have always said to me that the best continuing professional development they ever had was going into other schools.”

Collaboration between schools is nothing new, but headteachers like Ms Stanton have seen their roles redefined - they are now officially “system leaders”.

System leadership is a new buzzword popular with policy-makers and currently being hotly debated at education conferences.

The think-tank Demos recently issued a paper on it, and it is a theme of the National College for School Leadership’s conference, which starts on Monday. One of its forthcoming reports is entitled System leadership in action.

So what is a system leader? They are heads and other senior staff who are working for the success of other schools as well as their own. While working to build capacity and improve their own schools, they are also forging alliances and influencing the education agenda outside.

Given a spate of education reform, we now have to think differently about school leadership. Under the Every Child Matters agenda, for example, some schools have already taken on a range of services for their local community. So leaders now have to work not just in their own schools, but also across the education system and beyond.

Such roles are empowering for school leaders, increasing their influence within the system as a whole. But system leadership also brings huge challenges just as heads are bowed under the pressure of increasing government initiatives.

“What is expected of us as school leaders is immense,” says Dr John Dunford, general secretary of the Association of School and College Leaders.

“It requires an outward-looking partnership approach if we are to move from school improvement to system improvement.”

Will this collaborative approach thrive in the new education landscape proposed in the current Education Bill? Critics argue that the creation of a radical new school system with self-governing trusts and driven by parental choice, will increase competition and reduce collaboration between schools.