Maybe "banned" isn't the right word, but I understand it used to be BBC policy to exclude Irish language from programming and I've heard that at one time the BBC in N Ireland even avoided Irish traditional music. The half hour a day, by the way, is on radio. There is just an occasional feature programme on tv* and sometimes series for schools; but while we have our own BBC Radio Ulster and Radio Foyle, only a small portion of the tv programming is locally made. Chinese language and Ulster-Scots programmes have also been broadcast on BBC Radio Ulster in recent years.
*tonight: "Ceol i gCuideachta" with Iarla ÓLionaird of Afro-Celt Sound System is on before Newsnight.

I met an old man who told me he had joined the IRA as a youth because of the repression of Gaelic football.

Seeking more specific information, I looked in a slim book by Vincent McKee Gaelic Nations politics of the Gaelic lnguage in Scotland and Northern Ireland in the 20th Century. London: Bluestack, 1997. McKee gives a lot of detail about education; the Unionist government for years placed restrictions on the amount of Irish that could be taught in schools and what forms (years/grades) it could be taught to. For example, at one time schools were allowed to allocate a maximum of one and a half hours a week to teaching the language, though they could offer extra-mural classes outside school hours. That was done in some Catholic maintained schools, not in state schools. Liberalisation began in the sixties; by then Irish had finally died out as a native language in areas such as the Sperrins, glens of Antrim and Rathlin Island, where it had been in gradual decline into the 1950s.

What McKee says about broadcasting in Unionist controlled Northern Ireland from the 1920s is that "Quite simply, Gaeldom was treated by a subversive culture, unwelcome in the state schools, effectively blacked out of state broadcasting, and denied both recognition and public funding for its arts and cultural projects" (p28) and "Unionist hostility was futher pitted against Gaelic games, which were denied public sponsorship and effectively kept off the the screens of BBC Northern Ireland and Ulster Television until the late 1960s. So also were Ceilidh dancing and Irish music similarly curtailed, while Gaelic arts were kept to the periphery without official funding." (p 32)

The first Irish language medium primary school in Northern Ireland opened in 1971; it qualified for Dept of Education funding 13 years later Broadcast media coverage of Gaelic games began in the late 1960s and was gradually expanded. "...Irish language coverage was exempted from the thawing process. By 1985 there were no regular Gaelic medium programmes of either a utilitarian or educational kind. Nor did the cultural activities - including musical fleadhs, ceili dancing festivals, Gaelic drama etc ... receive broadcasting coverage." (Scottish media on the other hand has long been supportive of cultural activities, including the Gaelic singing competitions at the Mod). I can't remember when the first programmes featuring Irish were broadcast in N Ireland or when BBC started its Irish language broadcasting unit; according to McKee it must have been after 1985 anyway.

I don't know that lack of official support hindered the music (a question for another thread perhaps). As for the language, voluntary groups such as Comhaltas Uladh did significant work - and the fact that there were Irish-language publications, media and summer schools available just over the border and even a bit of funding from Irish language bodies in the Irish Republic did help. But as I have already said, Irish speakers and learners have greatly benefited from recent increased government recognition. They didn't get that recognition without campaigning of course; this is a positive feedback cycle.

Finally - a local news item which illustrates how you can campaign for language rights whether or not you have a bill for "Secure Status". The UK is a signatory to EU charters. A Derry pensioner with a long history of campaigning for rights to use Irish refused to get a new Smartcard bus pass for free travel unless he could apply in Irish. He also said equal rights should be given to Ulster Scots. Prionsias got thrown off a lot of buses over the past year. Finally he got a letter from the Dept for Regional Development stating that "The Department, mindful of its obligations under the Council of Europe Charter for Regional or Minority Languages has decided to make an Irish language version of the senior citizens concessionary fares application form. The Department would also look favourably on a similar request from an Ulster Scots speaker."