As the school year faded into the summer holidays I went on a semi-rural ride to two schools in south-east England.

They were both state schools, just a 20-minute drive apart, but they inhabited two remarkably different worlds.

Superficially they had much in common. They serve former market towns, still surrounded by agricultural areas but now drawn into the ambit of London, providing homes for large numbers of commuters and for workers in the fast-growing service industries.

Visiting the two schools underlined how much a school's success is determined by the communities it serves

The similarities end there. School A is a highly selective, ancient state grammar which regularly appears near the top of school league tables.

On the hot, clear-skied final day of term it seemed an idyllic place to teach or learn amid its attractive red-brick buildings and stunningly beautiful gardens.

The students are bright, keen, and motivated. Parents turn out in very large numbers for school events. The governing body is packed with professionals.

Teaching, not containing

It is the sort of school teachers find hard to leave. Many have been there for 20, even 30, years. Some are Old Boys.

And who can blame them? It is a civilised place where you can teach rather than operate crowd control and where extra-curricular activities such as music or sport are of high quality, well-equipped and taking place in beautiful surroundings.

The school has a strong sense of community and continuity. I met one former teacher now aged 90. He still lives nearby, regularly visits the school and, despite being retired for more than 30 years, is still in touch with many admiring former pupils.

School B is a primary school just 15 miles nearer to London but on a different planet.

Deceptive appearances

Yet first impressions suggest similarly advantageous circumstances. It has light, airy, well-designed three-year-old buildings. It is located on a new housing estate which includes expensive, gated "executive-style" homes.

The more you find out ... the more you realise that deprivation is not just about poverty

There are lots of jobs in the area. But the community is not particularly settled. It is a boom area which has attracted many incomers.

Houses have gone up faster than community facilities. Apart from the school, this large housing estate has no other community buildings.

The more you find out about school B the more you realise that deprivation is not just about poverty, it is also about lack of parental support, social division and the break-down of community.

Inclusive policy

The staff at school B are very committed teachers. They also seem to have had the role of social worker and substitute parent dumped on them.

The school is proud of its policy of inclusion. It accepts the many pupils who have been excluded from other schools - some more than once.

Talking to the head teacher, it soon emerges that the apparent affluence of the estate is misleading.

Yes, there are some very expensive houses. But the families who live in them send their children by bus to private schools - with the added advantage for working parents of having the children picked up early and dropped home late.

As the estate has grown, the houses have become smaller and more tightly- packed. Much of it is "social housing".

Overcrowded

The more the school takes in excluded or transient children the more its test scores suffer and the more the middle-class parents move elsewhere. But the school remains full because new houses keep going up.

Many of the children come to school hungry

Although just three years old, school B is now so overflowing that it has no fewer than 14 "temporary" demountable classrooms. I wonder if this is a record?

But overcrowding is not the greatest of the school's problems. Parental neglect and lack of community take an even bigger toll.

Many of the children come to school hungry. Some, according to the head teacher, will have spent an hour or so before school sitting in the garage because their parents have left early for work.

Many will spend more time on their own after school, either "home alone" or locked out of their houses waiting for parents to return from work.

Fragile families

Parents in this area have mortgages which they can only just afford to pay. They cannot afford to work fewer hours. They are hamsters on the modern treadmill of commuting, work, and materialism.

Partly because the estate is new, with many incomers to the area, many far away from their extended families, and many working long hours, family social ties are weak. The estate has no kids' club or community centre to provide alternative childcare or activities.

Many children, as elsewhere, live with a step-parent. Many parents are on their second families, stretching their finances and their time and affection. Sometimes the children of the first marriage are not always so welcome by the new partner in the second.

The children had already left for the summer holidays when I visited. The staff were packing up but were already talking about coming in during the holidays: The head likes to have someone there most of the time knowing that children will turn up at the school as they have nowhere else to go.

What to do?

What a contrast the two schools offer. School A is academically exclusive, taking only the brightest. School B is inclusive in its aims but - because of middle-class flight - its pupils represent a narrower social and ability range than you would expect.

Many would condemn school A's exclusivity. Yet it offers an excellent broad education to bright students irrespective of ability to pay. To destroy its unusual status would seem, to many, an act of vandalism.

But school B represents the other side of the coin. Because it is open to all comers, including those not wanted elsewhere, it unintentionally frightens away some of the very parents whose children would give it a genuinely comprehensive intake.

Should the school do more to attract and keep those middle-class parents? Would that inevitably mean shutting the door on some of the most socially-excluded and demanding children? Who would look after them if the school didn't?

I do not know the right answers to these questions. But visiting the two schools underlined how much a school's success is determined by the communities it serves. And this is not just a matter of money but of something the sociologists call "social capital".

Bowling alone

"Social capital" may sounds dry and theoretical, but it is a measure of the changes that are impoverishing our communities. It is defined by sociologists as the benefit or reward we gain from the sum of our community activity.

The best analysis of its modern decline comes from an American academic, Robert D Putnam, in his imaginatively-titled book, Bowling Alone.

Using the metaphor of the ten-pin bowling leagues that were the social cement in 1950s American communities, Putnam describes how Americans today increasingly "bowl alone" rather than in social leagues.

He shows how people have become increasingly disconnected from their neighbours, friends and local social structures.

It suggests that broader social policy is every bit as important as education policy in determining educational achievement

Membership of parent-teacher associations, sports groups, political parties and organisations such as the Boy Scouts or Rotary are all in sharp decline.

I suspect a similar trend is true in Britain and it particularly affects communities like the one served by school B. Putnam shows how the decline of social capital is not just about the loss of neighbourliness.

Communities with less social capital have higher teenage pregnancy, child suicide, pre-natal mortality and crime rates. They also have lower levels of educational achievement.

This is perhaps rather depressing for educators. It suggests that a school's success depends entirely on the neighbourhood it serves.

That is perhaps too defeatist. After all, we know there are many examples of schools that have done well "against the odds".

Nevertheless it suggests that broader social policy is every bit as important as education policy in determining educational achievement. Schools and teachers can only do so much to rectify a lack of genuine community in the areas they serve.

We have to rebuild our local communities, from the family unit upwards.