By Alison Smith BBC News education reporter

Tony Blair saw Dunraven School's "banding" system last week

Last week, Tony Blair visited Dunraven School in south London to see how it works in practice.

"There is real affluence and real deprivation cheek by jowl here," head teacher David Boyle said. "But we have always made success out of our diversity."

"Twenty years ago our reputation was one of a caring school, but of one which didn't necessarily deliver academically."

In the past the admission system at Dunraven School in Streatham, south London, was based on three factors: siblings, social and medical need and distance between home and school.

The school set about changing that reputation. Taking control of its admissions system was one part of the jigsaw.

It switched its admissions system to banding because it wanted to have a "properly comprehensive intake".

The ability range had been "skewed towards the middle and lower end of the spectrum".

After an admissions test, it places children in one of five ability bands. The school takes 20% of its annual intake from these bands. Thereafter the three usual admissions criteria apply.

"We don't select the best 20% from each band," Mr Boyle said. "That's not what we're about."

'Happier intake'

He said things had improved year on year, and on a number of levels. Now, he says anyone considering the school knows "their child has the best chance possible".

"On the back of the banding system we have become an increasingly local school.

"In the past many families in the area didn't feel confident the school could deliver what they needed.

"Now we know families who may not have considered Dunraven or even the state system are looking at us as a real alternative."

Mr Boyle suggests it leads to a happier intake of pupils because "they are more likely to find other children here like them".

"In terms of ethnicity, cultural factors and ability, we do represent our community fully."

But he stops short of saying it is a fairer system.

Disadvantages

Banding was used by the now defunct Inner London Education Authority in the 1980s, and survives in a handful of London boroughs.

If it is adopted on a wider scale it will give some children hope of getting into a school they may not otherwise have access to, but could mean other students are turned away.

The government is keen to increase choice for children from less privileged backgrounds.

The system is "absolutely transparent" and cannot be played by well-off families, Mr Boyle said.

Under banding it is unlikely a child would gain a place at a school ahead of one who lived closer. But this could happen as a result of other criteria used in conjuction with banding.

Dunraven's popularity is shown by the number of students it turns down - last year the school received just over 1,600 applications for 192 places - though in Lambeth there is historically a lack of secondary school places.

Balanced intake

So when schools like Dunraven are so over-subscribed, do parents really have a choice - and if we seek a fairer admissions system, can choice be increased at the same time?

No one school can do that alone, Mr Boyle said. But Streatham now has the choice of a "good local school".

"Banding has allowed us to achieve a balanced intake, and to ensure we are admitting children who live close to the school - from all backgrounds, which is important."

The notion of a right to a choice has undoubtedly led to disappointment for some parents.

Where all the local schools are strong, Mr Boyle says, there will be more choice because parents have options they deem acceptable.

Each school can and should still be able to admit the range of students it wants to, but it can achieve this in a balanced fashion, rather than through selection.

Dunraven might be expected to expand its intake if it continues to attract local families and those from farther afield.

It cannot do this without changing the nature of the school, the head teacher suggests. And this he appears reluctant to do.

Despite having 1,200 students, relationships between pupils and staff are good and contribute to the school's success.

But schools need to find their own solutions.

"Adopting banding will not automatically improve what is on offer for young people," Mr Boyle said.