Richard King explores the past and present of the second homes debate in Wales, revisiting the story of Meibion Glyndwr – active terrorists on British soil for almost 15 years.

In Wales it is compounded by the fate of Cymraeg, the Welsh language.

It is felt by many that second homes contribute to the fragmentation of Welsh-speaking communities and pose a threat to the survival of the language.

It's nothing new. Beginning in 1979, Meibion Glyndwr – Sons of Glyndwr (Owain Glyndwr being a soldier who led a revolt against English rule in the 1400s) – responded to this threat by carrying out hundreds of arson attacks and fire-bombings. Initially targeting second homes and holiday cottages in Welsh-speaking areas, the campaign later expanded to target estate agents, English-owned businesses and the offices of police and politicians, accompanied by stencilled letters containing extravagant nativist threats. Hundreds of properties were damaged and destroyed. It lasted until 1994 and only one person was ever convicted of a related offence.

The Meibion Glyndwr campaign was audacious and shocking – and utterly ineffective.

In the thirty years since the last attack Wales has gained its own parliament and with it a measure of power to decide its own fate. And as elsewhere in the UK, the issues around second homes have only become more urgent. One of the newer policies enacted by the Welsh government is a council tax premium on second homes, with local authorities able to decide how much of a levy to apply, up to a possible 300%.

Writer Richard King visits Abersoch on the Llyn Peninsula, a village very much at the sharp end of the current situation and hears from some of those who lived through the Meibion Glyndwr campaign.

Featuring Robat Gruffudd, Amanda Jones, Richard Wyn Jones, Alun Lenny, Louise Overfield and Eifiona Wood.

With grateful thanks to Sian Howys, Meic Parry and Dylan Roberts.

(The programme contains an archive recording which refers to RS Thomas as a non-conformist minister. RS Thomas was a priest in the Anglican Church in Wales.)