The ruin of Thetford in the 1950s and 1960s by housing developers, not least the Greater London Council, has left it a pretty awful place. Once a small town of barely 5,000 people, it now has almost eight times that number, mosly in bland former council estates along clogged roads which hem in the historic centre with its modern shopping precinct. But on the eastern outskirts, just behind the Tesco superstore, is one of Norfolk's prettiest little churches. Kilverstone Hall will be familiar to a generation of East Anglian children as home to a lovely zoo which specialised in exotic monkeys. But the zoo went bankrupt in the 1990s, and the monkeys have moved on. Today, that part of the park not overtaken by superstores has become a business centre, but beyond the Hall the view is as lovely as ever. Visitors will remember the idiosyncratic water tower designed as a kind of late Victorian castle turret. But more special is the delicious Art Nouveau lychgate in the corner of the fields, which leads through into the graveyard of the round-towered St Andrew, sitting in the fields a quarter of a mile from the nearest road.

St Andrew is a charming building, lovely of proportion, a squat, castellated round tower against a heavily restored Norman church. The south doorway is original, but the other Norman features, the west window and the tub-like font inside, are an 1850s pastiche.

We came here to find that a Flower Festival was in progress. I used to be wary of visiting churches on these occasions, but I've come to find that the bedecking is rarely intrusive. It usually doesn't cover up anything important, unless the church has a significant font or a rood screen, and I knew this was not the case with Kilverstone. We stepped into the tiny nave to see that the displays were not much bigger than you'd find for a typical wedding. Another reason I've warmed to flower festivals in recent years is that they do give you a valuable insight into the mind of the parish. In the last few months, I had visited two churches in Suffolk holding flower festivals, and had been fascinated by the treasure trove of local historical items which the people had collected together. One festival had been themed on the subject of the 1950s, while the other had depicted 'weddings through the decades'. Both were excellent, without spoiling an exploration of the church itself. The items of interest were not the flowers, of course, but the photographs, books, clothes and the like which they'd used to augment the displays.

The other thing I like is that you get to meet local people, and there's no suspicion about your visit. They actively want you to take photographs. The two ladies on duty here were very accommodating, turning off the bright lights so that we could photograph the glass, and even offering to move a display, which I wouldn't countenance, of course. The theme was 'United Nations', and each display depicted a different country. There were objects which you might associate with the country in question: there were clogs for Holland, for instance, and a beret and onions for France. It was all cheerfully done. I couldn't help smiling, especially on overhearing a conversation between two other visitors:

First Lady: "This one represents Japan." Pause. Second Lady: "It's a bit minimalist, isn't it?" First Lady: "Well, she did go to Art School." The jewel of St Andrew is the gorgeous Arts and Crafts window on the south side of the Nave. Mortlock thought it was an early work of Leonard Walker. A curiosity is the Royal Arms of George I carved in plaster above the tower arch. The inscription says that they were the gift of Charles Wright in 1716. Some roundels on the north side depict the crucified Christ with the Blessed Virgin and St John. At first sight, I wondered if they were fragments of older continental glass worked into a new arrangement, but I think they are probably late Victorian. Nine lost boys are on the war memorial. They are also remembered on a beautiful Art Nouveau wellhead, back up on the road to East Harling.