For the past 100-odd years, a vast, gloomy, rather murky-looking painting of The Last Supper has loomed above the altar at St Michael & All Angels church in Ledbury, Herefordshire. It is 12½ft wide, 8 ft tall and was hung so high on the wall that, even if the paintwork hadn't been obscured by layers of cheap varnish and centuries of dirt, the church's 100-strong congregation would never have been able to make out its finer points. That's why nobody had noticed the exquisite brushwork on some of the apostles — not even the striking-looking chap on the left in his golden robes who bore an uncanny resemblance to the 16th-century Italian painter Titian.