Imagine, if you will, two nations, both quite similar to each other but with enough difference that they sit uneasily side by side. These nations share the same landmass, the same economic fortunes, the same levels of neglect by the outside world. One of those nations has survived through sheer insistence, the other seemingly in permanent decline unable to rediscover its voice, both in a permanent state of crisis. Speaking of the latter nation, the novelist Alun Richards explained on the BBC in 1963 that:

Today, there is not the same dependence on one industry, but as a result, there is not the same common bond between workers in different industries, or the feeling for place common to people whose home and place of work are the same. And this, perhaps, is a far greater loss than the Welsh language, for there is nothing more hideous than the dormitory town, nothing more anti-life than the suburban squalor and anonymous isolation of cosy collections of houses whose inhabitants feel no common identity.

That nation was represented – for better or for worse, forever and ever, till death do us part – by the Labour Party. These days, the remnants are quite as willing to put their cross next to a UKIP candidate as they are a Labour one. The other nation is, of course, that which has at various times been represented by the Liberal Party and Plaid Cymru. They share certain bonds with the Labour nation but exist in their own separate sphere.

Just a few years after Alun Richards’s broadcast, the two nations inevitably came to blows: in Carmarthen, in the Rhondda, in Caerphilly, and finally at Merthyr Tydfil. Much has been written about the steady breakdown of Labour’s colossal authority in Wales – for those interested in what happened in North Wales, Andrew Edwards’s book is well worth reading, as is Paul Ward’s biography of Huw T. Edwards – and it will continue to occupy historians and commentators alike. I don’t wish to rehearse the arguments too much here, for the purpose is to make my own. Suffice to say that a consensus appears to be emerging around Labour’s inability to “speak” to emerging generations with less attachment to heavy industry and the ability Plaid Cymru, in particular, to pick up disparate voices from the socialist and liberal Left. I’ve written about that momentum here previously.

Of the series of by-elections in South Wales during Harold Wilson’s second government (that is, 1966-1970), the most iconic is undoubtedly that which took place in Carmarthen in 1966. Upon the death of Lady Megan Lloyd George, the Labour MP for the town for nearly ten years, Gwynfor Evans, Plaid Cymru’s president, famously fought and won the by-election (reversing the third place he had achieved at the General Election a few months before). It was an obvious political moment: he declared that Wales had woken up, finally, and was on the way to throwing off the ‘English yolk’. Such phrases are rather trite, but are indicative of the rhetoric that Plaid was willing to throw around at that time. Gwynfor Evans, like Megan Lloyd George, was more Liberal than Socialist. Traditionally a Liberal stronghold, Carmarthen became winnable by Labour only in the 1930s (being won by Labour for the first time at the 1929 General Election) – amongst the last of the South Walian seats to fall to the party. From 1945 to 1957, indeed, the seat had been held by the Liberal Party. Whatever the circumstances of her high-profile defection from the Liberals to Labour, Megan Lloyd George remained, to all intents and purposes, the radical liberal she had always been. Gwynfor Evans readily stepped into her shoes – he had, after all, been a county councillor for Carmarthenshire since 1949.

Although it was certainly a shock for Labour to lose the Carmarthen seat at the by-election – a shock that was then compounded by the by-elections in Rhondda West in 1967 and Caerphilly in 1968 – it was, it seems to me, as nothing compared with the extremity of losing control of Merthyr Tydfil in 1970, a seat that had been consistently held by Labour since 1922 and which, when the borough had had two members, had also been the seat held by Keir Hardie. Losing Merthyr sent a shockwave through the Labour Party and exposed the party’s greatest weakness: through venality and corruption it was becoming the very opposite of what it believed (through a combination history and mythology) itself to be. It was already a theme in popular commentary: the novelist Glyn Jones, himself a native of Merthyr Tydfil, had caused a minor scandal in 1960 with his novel The Learning Lark, which tackles corruption in a Valleys council (identifiably run by the Labour Party). Wales, of course, was not alone in experiencing this kind of breakdown: Sid Chaplin’s novels on the North East of England expose similar traits (and find echoes in that classic TV drama Our Friends in the North).

First elected at a by-election in 1934, Merthyr’s well-loved MP going into the 1970 General Election was SO Davies. As the last Welsh MP directly sponsored by the South Wales Miners’ Federation and, in essence, the last veteran of the Independent Labour Party (ILP), SO Davies was someone who expected to leave parliament on his own terms, not through the ambitions and conniving vices of younger members of the national Labour Party and the Merthyr Tydfil constituency party. But it was a toxic combination of the latter that resulted in SO being ousted as the official Labour candidate and Tal Lloyd chosen in his place. It was a catastrophic mistake and so it proved at the General Election when SO comfortably defeated his rivals. He was the first Independent to beat the party machine since the Second World War and died two years later, dying in his bed after finishing his constituency business for the day. When the result was announced during the BBC’s General Election coverage the jaws of the presenters dropped. For days afterwards cameras and reporters camped in Merthyr – notably outside Gwynfryn, SO’s home – securing interviews with him, in English and in Welsh.

The Labour machine had believed itself invincible. After a few wobbles in the borough during the early 1960s – with the rise of Plaid Cymru and later a ratepayers’ association in areas such as Dowlais and Penydarren – by the end of the decade that challenge had been seen off and Labour remained in control. By the time Harold Wilson retired as Prime Minister in 1976, however, Labour had lost control of Merthyr Tydfil County Borough to Plaid Cymru. In neighbouring Rhymney, too, Labour’s majority had evaporated. The Merthyr Express reflected on Plaid’s victory at the local elections in 1976 as being a victory for ‘Liberalism with a Welsh accent’ and I think that is quite an apt conclusion, but somewhat misleading all the same. The effects of the 1970 election on Labour in Merthyr were shattering: those who had supported SO Davies were ejected from the party and they went on to form their own Independent Labour. Several were elected as councillors in subsequent years but by 1976 they sat as Plaid Cymru, never able to reconcile themselves to Labour.

At times examining Welsh politics in the 1960s and 1970s can appear a little like muck raking – corruption, venality, personality battles, fluid lines of conflict and cooperation – but there is a necessity to it all. Gwynfor Evans’s victory at Carmarthen in 1966 was not as important as historians and commentators have led us to believe. Looked at in the cold light of winter sunshine, it was far more of a continuity than a break. SO Davies’s victory in 1970, on the other hand, was utterly shattering. It, more than any other Welsh by-election since the Second World War, explains the state of politics as they are now. Today’s Wales, the child of the Miners’ Strike, was conceived in Merthyr in the summer of 1970, not in Carmarthen in 1966.