Once, Belton was in Suffolk. But in 1974 they moved the border; and so, as we headed north from the lovely Lothingland lanes into what is now the somewhat dismal outer suburbia of Great Yarmouth and Gorleston, we were in Norfolk once again. At the end of the Second World War, Belton was a remote village of not many more than the 600-odd people who'd lived here at the time of the 1851 census, when the population peaked in many rural East Anglian parishes. In the 1940s, Arthur Mee came this way for The King's England: Suffolk, and remembered Belton's churchyard for a beautiful view of the village and its winding street among the trees below. In the 1960s, East Suffolk county council made plans for a massive expansion of villages in this area. Today, the population of the parish is not much less than 5,000. Belton has the worst of both worlds: it is a bit of suburbia which has floated off, and drifts in isolation from the urban conveniences, but is without any of the charms or attractions of much of rural Norfolk. My heart sunk as we threaded our way through the estate of look-alike houses to find a lane that hardly seemed to be there, as if it had been forgotten, or left behind. This led out on to the edge of the village, and there at a sharp bend in the road was the church of All Saints.

All Saints is a big round-towered church, albeit a rather stark one. The chancel and tower were both completely rebuilt in the 1880s - the tower had collapsed about thirty years earlier. The nave was reroofed, but fortunately these are the original walls, thus ensuring the survival of an extensive scheme of medieval wall-paintings.

The first indication that all was not well came as we got out of the car. The church sign board was chipped and faded. This in itself is not unusual, of course, but the board had been overpainted with coils of mindless graffiti. I wondered if they might be the tags of rival gangs. Curiously, the sign underneath gave no indication of the dedication of the church, but it did promise that the morning service would have a welcoming and informal atmosphere, lively worship, relevant teaching, healing ministry, and be all-age friendly with children's groups. It seemed a strange list of promises in such a spot.

We walked up to the church, but already I could see the large padlock on the porch doors. This wasn't unexpected. It's a strange thing: East Anglia has one of the highest proportions of open churches anywhere in England. Perhaps 75% of all Anglican and Catholic churches in Norfolk and Suffolk are open to strangers and pilgrims every day for private prayer and meditation. But this percentage hides the fact that in most parts of East Anglia just about all the churches are open or accessible. The statistics are skewed by the towns of Great Yarmouth and Lowestoft and their wearisome sprawls of suburbia: here, virtually all the churches are kept locked without any access details. I had hoped that Belton's distance from the centre of Yarmouth might mean it had escaped this gravity of indifference, but it was not to be. And then, another curiosity: a sign behind the metal bars told us that Belton church is no longer used for services. Now, apparently, the local high school is home to the Anglicans of Belton; or, at least, it is on a Sunday. We rattled the doors, but they really were locked. I stood back, and looked along the length of the south side, and saw the ivy beginning to creep up to the eaves.

We walked around the church. The priest door had also suffered from a graffiti attack, and several headstones to the east of the church were broken. Beer cans and other litter were scattered around. We walked around to the north side to the surprise of a large modern extension built on rather awkwardly to the former north doorway. Coming closer, it became obvious that this part of the building, at least, was still in use: There were notices announcing activities for mums and toddlers and the local youth. The windows were blocked by metal grills. It looked a little like the high security unit of a psychiatric hospital. Blu-takked up behind one of the grills was a printed and laminated notice: Jesus is Alive!

Perhaps it was a kind of totem, to ward off the evil spirits that might otherwise encroach upon a sacred building which had otherwise been abandoned. Or perhaps it was simply to remind us of a Truth not evident in such a place. Whatever, this perfunctory little notice proclaiming Christ behind bars seemed to sum up Belton church for me. I got home, and e-mailed the Rector named on the graffiti-spattered sign, but I didn't receive a reply. It took a visit to the Belton village website to discover the answer. In 2002, the services had moved to the school because of the inadequate heating system in the church, and they had never come back. The website said that the congregation was growing, and the move had been popular. It claimed that the church was used for 'special services' throughout the year. Instead, the congregation meets in 'cell groups' in people's houses during the week, and gets together on a Sunday. It said that the Bishop of Norwich had given his blessing to the arrangement.

It also said that 'the church building is not being neglected', but I'm not sure I'd agree. The graffiti, the litter, the ivy climbing the walls - these are all signs of neglect. They aren't irredeemable, but a friend who works for the Churches Conservation Trust visited Belton church after I had told him about it, and observed that they are at the start of a spiral of neglect which will one day lead to ruination if something is not done about it. It is tempting to blame the local parish for dereliction of duty, but in all honesty it isn't really their fault. An evangelical protestant congregation of this kind cannot really be expected to agree that there is a sacramental and liturgical significance to a church building, or to see it as an act of witness in itself. Why should they? It would be much more sensible if there was a mechanism by which a local Anglican parish could give up care of its medieval church when they realised that they no longer welcomed the burden of caring for it and would rather have services in the local school, thus passing the old church on to another agency which might look after it: but there isn't.

The worrying thing is that All Saints is a building of some historical significance. Despite its considerable Victorian rebuilding, the 13th and 15th century wall paintings in the nave include St James, The Three Living and the Three Dead, and St Christopher. Cautley described them as 'notable', but Mortlock found them very faded in the 1980s, with only the St Christopher really recognisable. They would benefit from restoration. The 15th Century rood screen is said to be particularly fine: Mortlock describes it as a better version of the one at Fritton. Mee identified the four Latin Doctors as well as St Margaret and St Hilda on the panels. The 1870s reredos is by the Beverley artist James Elwell, an influence on Eric Gill. And so you see, it is quite important that this church is in safe hands.

We wandered back down to car, deep in thought,and then John noticed something which I had forgotten, but should have remembered. Just off the path is a simple stone memorial to a former Rector of Belton and his wife. This is not unusual, of course; but their son grew up to be the most important East Anglian church historian of the 20th Century. Henry Munro Cautley became an architect, and in the 1930s and 1940s conducted a great survey of all the medieval churches of Norfolk and Suffolk. These two huge books are classics of their kind; he reawakened the church antiquarian impulse at a time in the 1930s when there was a rising enthusiasm for amateur exploration and rediscovery of the past. John Betjeman was a great admirer, and there are echoes of Cautley's work in Betjeman's own church writing. Cautley himself lived and died in Westerfield, on the outskirts of Ipswich, where he is buried under a tree in a forgotten corner of the graveyard. But it seemed ironic that, in this place of all places, with a significant medieval church teetering on the edge of being lost to us, his story began.