Gwenno Teifi, a 19-year-old student from Llanfihangel-Ar-Arth, Carmarthenshire was ordered to serve her custodial sentence at a young offenders unit in Gloucester.

Teifi was one of five activists each ordered to pay £50 in court costs and £150 in compensation to the radio station after they were found guilty last April of causing criminal damage to the Radio Carmarthenshire studios in Narberth.

The members of Cymdeithas yr Iaith Gymraeg, the Welsh Language Society, stormed the Narberth head office of Radio Carmarthenshire and its sister station Radio Pembrokeshire in July 2004.

They were protesting that, the then newly-established, Radio Carmarthenshire was failing to live up to its licensing agreement by only broadcasting limited programming in the Welsh language

Teifi, a student at Aberystwyth University, refused to pay her £200 bill, despite knowing that a custodial sentence was inevitable.

“I am not scared of going to jail as I’m going for something I believe in," she said.

"I don’t want to pay money to an organisation which is ignoring Welsh speakers where it broadcasts.”

Teifi received a five day custodial sentence yesterday. She is the first member of Cymdeithas yr Iaith Gymraeg in a decade to spend time in jail.

Teifi’s sentencing sparked a fresh round of protest with members of the language society chanting "Language Act, Here's the Chance," after magistrates announced the prison term.

Protestors then demonstrated outside the court until Teifi was driven away from the scene in a security van.