The letters, sent to 19 families, were from the militant Welsh nationalist group Meibion Glyndwr - the Sons of Glendower. They warned the families to leave Wales by St David's Day - 1 March - or be burned out.
The militants are waging a war of nerves, a war in which rational dialogue has become the first
casualty. Professor Matthew Seaman, 84, one of four English residents on the Lleyn peninsula, who has received threats, describes Meibion Glyndwr as 'a boil on the bum'. Owen Williams, a local councillor jailed in the Sixties for blowing up an English power line, retorts: 'He's just a bum on the boil.'
No one knows whether the militants are bluffing. There have been some 200 firebombings over the past 10 years, but previously the Meibion Glyndwr - named after Owen Glendower, the 15th- century self-styled Prince of Wales who led an abortive rebellion against Henry IV - have
always struck without any warning.
In the peninsula, which juts out below Anglesey off the north coast, the once-gregarious English community is bracing itself. The Lleyn four have little in common except, police believe, their appearance in controversial news stories in the local press last year. One has since gone; the others are determined to stay. Ian Lee, a hotelier in Morfa Nefyn, left Wales after being threatened in October and now lives in Bridgnorth, Shropshire. But he insists that it was the recession that forced him out.
The locals might see it differently. After a Welsh industrial tribunal ordered Mr Lee to pay more than pounds 7,000 to former employees of his hotel last July, the Welsh-language paper Herald Cymraeg quoted him as saying: 'It's people like the Welsh who create people like Hitler.' His views remain unmodified today.
'If I had my way I'd be worse than Hitler until I'd sorted them out because people are absolute bastards,' he said. 'Forget the Sons of Glendower. The problem is with John Major and the economy and hotels going out of business. The economic problems are probably the same as in England, but the bottom line there is that they hate the English. At the end of the day they want to see them fail.
'A friend warned me that I was going to a nationalist area and I believed, very navely, that I could overcome it by being polite and nice. It was a waste of time. They knocked hell out of us. They wrote 'Go home, English bastards' on the toilet wall and every time we painted it out they wrote it back again. Make no mistake, they're not idle threats - if they say they'll do something, the chances are they'll do it.'
Carl Hollins, son of the television comedy writer Carla Lane and owner of a holiday home in Abersoch, has also been told to go. He became involved in Welsh politics after Ms Lane bought St Tudwal's Island East off Abersoch two years ago and ran into problems with local planners. He later publicly likened local council leaders to Gerry Adams, the president of Sinn Fein.
Mr Hollins, who lives in Liverpool and does research work for his mother, has also not changed his views. 'My suggestion was that they were in fact political spokesmen for the urban terrorist organisation in Wales,' he said. 'Apart from securing the letter- box against firebombs, I shall rely on the integrity of the police. Any terrorist threat from these people has to be taken some notice of. The feedback I've had from the indigenous population is that they're embarrassed. Even the nationalistic ones, in the pub etc, droop their heads, touch their forelocks, in shame really, when they hear of this sort of thing.'
Ms Lane said: 'The house we've bought in Abersoch is called Glendower and I've said to Carl 'Oh, they'd never burn a house down with their own name on it'. When I bought the island I had some Welsh stone set in a circle and I was called a witch. I had a small croft there with a tin roof and when I had it reinstated, in Welsh stone, employing Welshmen to do it, the planners went over there and accused me of living in it to escape the poll tax.
'The Sons of Glendower are not to be condoned but they have the same passion as people, like me, who love animals. When you go in groups you lose your sense of reasoning.'
Robert Newton, who runs a cafe in Abersoch, believes he is on the Glyndwr hit-list because of a dispute over a footpath crossing his property at his home in the nearby village of Llanbedrog. 'You have to take this threat seriously,' he said. 'On the other hand, it seems so pointless, so ill- founded, you tend to think it will blow over. We'd been trying to divert the footpath because it crossed the front of our property. We went through all the right channels and our first application was turned down. There's been a little bit of ill-feeling but nothing to warrant this.
'This is a Welsh-speaking community. We don't take much part in village life but we try to speak Welsh in a very basic way, the little pleasantries. We're not leaving. In one or two years' time we might put the house on the market. We tend to move around a lot anyway. We're not afraid. The police have been very supportive.'
Professor Seaman, former head of British Oxygen and still an international technical consultant (he was in Russia last year advising President Yeltsin about privatisation), has been a prime mover, from his home in Nefyn, in Welsh economic development for 30 years. Locals are astonished to see him on the hit-list.
'It's just whatever particular irritant tickles the idiosyncrasies of these schizophrenics,' he said. 'They daubed my house with 'English pigs go home' some time ago and the whole village turned out and cleaned it up and the president of Plaid Cymru wrote me a nice letter of apology.
'Their letter is utterly and stupidly irrational. I've worked more successfully for Wales than any Welshman. I'm founder of the Nefyn Sailing Club which brings in a million a year in purchasing power.
'I've raised pounds 200,000 for the museum we converted out of an old church and saved a wonderful Welsh monument in the process.
'I and my family have lived here for 60 years. We're very friendly with everyone and hardly anyone takes any notice of these stupid people.
'The list is entirely random but the pattern is fairly clear. Like Carla Lane, one is picked out for no reason at all except that one is English, prominent and well known.'