Apart from an assortment of public houses, starting with the Snooty Fox in Southport when I was 16 and desperately trying to cultivate sideburns to make myself look older, I had never been a patron of anything until I was asked to (and this might not be quite the right word) patronise a fundraising appeal by the Parochial Church Council of St Mary the Virgin in the Herefordshire village of Marden. And it's a splendid cause: expensive repair work on a leaky church roof.

It's not just any old church, either. St Mary the Virgin was built in 1240, for heaven's sake, and even then it wasn't the first house of worship on the site. King Offa, of dyke fame, built a church in Marden in the late 790s, supposedly as an act of atonement for the murder in his nearby palace of the young king of the East Angles, Ethelbert, who had come to Marden to marry Offa's comely daughter Alfthrytha. Actually, I don't know whether she was comely or not, but not to get comeliness into a story of an eighth century princess would seem like a dereliction of duty. Either way, the invitation to marry Alfthrytha had come from Offa, and Ethelbert's adviser Oswald encouraged him to go for it. Mercia, of which Offa was king, was the most powerful kingdom in the country, and it would clearly be an astute move to marry into its royal family. It occurs to me that it would also, had Ethelbert and Alfthrytha shortened their names out of affection or convenience, have yielded a couple in which Ethel was the husband and Alf the wife.

Unfortunately, and despite Alfthrytha's enthusiasm for young Ethelbert, the wedding never happened. Offa's wife Cynethryth, a poisonous piece of work, thought that Ethelbert represented a threat, and suggested they should have him killed. There are various versions of what happened. Some say Offa refused to contemplate such a dastardly deed, so Cynethryth arranged it herself. With Ethelbert dead, Offa seized the opportunity to invade East Anglia, which he duly annexed to his own dominions, but was overwhelmed with remorse, and travelled to Rome to ask the pope how he might seek expiation. The pope told him that he must build a church at Marden. Moreover, a spring had miraculously appeared in the spot where Ethelbert's corpse had been thrown, so the church was built over the spring. It's still there today in the form of St Ethelbert's Well, which was a place of pilgrimage for centuries and where just last Friday I paid my own respects, albeit holding a piece of cheddar and pineapple on a cocktail stick, rather than a prayer book.

The occasion – and in my candid opinion there can never be enough occasions featuring cheddar and pineapple on cocktail sticks, still the king of canapés whatever anyone says about brie and cranberry parcels – was the formal launch of the appeal, which seeks to raise £75,000 by the end of this year, to supplement a grant from English Heritage. As patron I was asked to say a few words, and made a lame joke about EastEnders storylines seeming positively tame alongside the history of Marden church. It got more of a laugh than it deserved, perhaps because of the enduring power of St Ethelbert's Well, traditionally a place where the lame become strong. I like to think that old Ethelbert was looking down and touching me with the spirit of Tommy Cooper. And to discharge further my patronly duties, I invite anyone who cares about the future of a building with so much past to donate to the appeal: cheques payable to Marden PCC can be sent to David Lloyd, the appeal treasurer, at Woodbine House, Marden, Herefordshire HR1 3DX.