Long after it was built - around 900 AD - this church didn't so much fall into disrepair as became totally ignored, which is what saved it. I wish many other fine buildings had been ignored in the past, then this one wouldn't be so rare.
Over the years following the Norman invasion, the church was built up against on all four sides to form domestic dwellings. The main body served as a schoolhouse for many years, surrounded as it was by medieval additions, and you can still see the joist-holes where a floor had been added halfway up the walls, lowering the ceiling to a more manageable height.
It is a tiny little church, and when they hold weddings here, most of the congregation has to stand on the grass outside - but without a flat-screen projector to show them the action on the inside.
The reason (I believe) that the main tower is so high was to inspire a sense of loftiness in the congregation, who were used to very low ceilings and very small doorways and windows - not because they were all midgets in those days, but because it was a lot easier to heat houses during the long winter months. This is why four-poster beds were invented - you could keep the grand, lofty ceilings in your huge manor house, but have a dedicated, enclosed space to sleep in at night without freezing to death.
In 1871, the vicar of the church just over the road, looked up to see some ancient architectural features peeping out from the medieval rooftop abutments that surrounded the building in those days, and - correctly - guessed that there was an ancient church nestling in amongst them. The church acquired the property, and he set about demolishing the medieval parts of it, until a wonderful jewel of a Saxon church miraculously appeared from within.
It is one of the few churches that remain open to the public all day during daylight hours, and services have resumed there on a regular basis. Well worth a visit to Bradford on Avon - especially if you combine it with a trip to the medieval Tithe Barn just down the river, and the ancient bridge with a 'Blind House' prison which straddles it, in the centre of town.