To mark the occasion, the freshly elected Labour government under Clement Atlee affixed signs to the gates of each mine, which read: “This colliery is now managed by the National Coal Board on behalf of the people.”

In a leaflet handed out at the time, Attlee wrote: “The coal mines now belong to the nation.

“This act offers great possibilities of social advance for the workers, and indeed for the whole nation.

“If all alike – workers, National Coal Board and Government – shoulder their duties resolutely, and use their rights wisely, these great advances will be assured.”

The move was seen as a victory for workers.

Miners in Britain had campaigned for nationalisation in one form or another since about 1892, but it took decades of organised struggle – and, ultimately, World War 2 – to make it a reality.

World War 2 and the road to nationalisation

By 1919, campaigning from the Miners’ Federation of Great Britain – which saw public ownership of coal mines as a route to better pay and working conditions - had led the Liberal UK government to establish the Sankey Commission, which considered the possibility of nationalising coal.

The former site of Lewis Merthyr Colliery, Trehafod, now the Rhondda Heritage Park. (Picture source: Gareth James)

Though the Commission recommended coal mining be taken into public control, the UK government refused – but it continued to be a key issue for miners, as well as for the growing Labour party.

Labour had run in the 1918 election on a promise to nationalise mines with “an increased share of control for workers”, but by the next election, in 1924, had removed explicit mention of worker control from their manifesto.

Tensions over whether a nationalised coal industry should emphasise efficiency for the public or meaningful control for its workers continued into the following decades – and arguably, never ended.

During that time, the industry hit a slump.

Dr Ben Curtis, a south Wales industrial historian, said: “The interwar years were difficult, especially for the south Wales coal industry, for a whole series of reasons - overseas competition, the nature of the uses for the coal mined in south Wales, and so on.

“And certainly, the industry wasn't really able to perform adequately for the needs of the British [second world] war economy.”

When the UK entered into World War 2 in 1939, coal was central to the effort – the fuel not only warmed homes but powered factories, railways and ships. As mines overseas were rendered inaccessible by conflict, the south Wales coalfield – the largest in Britain – became all-important.

A mine in Cefn Bryn-Brain, Swansea (Picture source: Geoff Charles; National Library of Wales)

“During the war, the industry is placed under state control,” Dr Curtis said.

“We're still in private ownership, but they had to do what the government said, in terms of running the industry, in terms of having mining as a reserved occupation - a whole number of things.”

So great was the need to keep mines running that this “reserved occupation” status – exempting mineworkers from military service – also meant that young men could also be “drafted” into mining instead of the armed forces. Around ten percent of 18 year-olds at the time were “Bevin Boys”, draftee miners, so-called for Ernest Bevin, the Minister of Labour and National Service at the time.

.A tribute to the "Bevin Boys" in Staffordshire, England (Picture source: Flying Stag)

“Then there was the Reid Report, produced in 1945, about the future of the coal industry,” Dr Curtis added.

“It concluded that coal was too important an industry to be left in private hands – that they’d shown they weren’t up to the job, that it needed to be run as a state industry in order to make it a better place to work - and so that was the recommendation.”

When the Labour party took power from Winston Churchill’s Conservatives later that same year, plans to nationalise a raft of public utilities – not only coal, but electricity, railways, iron and steel -were set in motion.

Vesting Day and beyond

When Vesting Day came around, it was treated as a day of national celebration by mineworkers – the culmination of multiple generations’ worth of campaigning.

Signs were put up at around 1,400 mines across the UK to mark Vesting Day, the day on which UK coal industry assets were "vested" in the state.

“It really was perceived as a big deal, especially in south Wales,” Dr Curtis said.

“In Penallta [Rhymney Valley], miners and their families gathered around the pithead, waiting for the floodlights to be switched on.

“A band played, miners sang Mae Hen Wlad fy Nhadau, speeches were made – one apparently shouted - ‘private enterprise has had it!’

“At Duffryn Rhondda colliery, in the Afan Valley, there was a ceremony attended by pretty much the entire population of the surrounding villages.

“In the Rhondda Valley, there was a whole series of nationalisation celebrations put on through to February 1947 – concerts, exhibitions, mass meetings, and so on.

“This really wasn’t something that just happened on paper.”

Arthur Horner, a Merthyr Tydfil-born miner and General Secretary of the National Union of Mineworkers (NUM), was heavily involved in drafting the government’s Coal Industry Nationalisation Act.

Disused winding tower at Penallta Colliery, Rhymney Valley (Picture source: Chris Sampson)

Horner, a founding member of the Communist Party of Great Britain, had led on developing the NUM’s Miner’s Charter, which made demands including two weeks’ paid holiday, the five-day working week, and a stable and guaranteed rate of pay – as well as adequate pensions, improved health and safety, training for young people, and decent compensation for injured workers.

In part because of Horner’s influence, some of those demands – such as the five day working week - were implemented from the very beginning of nationalisation, and over the following decade all were secured.

The task ahead, however, was enormous. Along with more than 1,400 coal mines, the National Coal Board (NCB) took over assets including 225,000 acres of farmland and 140,000 miners’ houses, as well as shops, offices, and holiday parks.

A National Coal Board train, 1965. (Picture source: Ben Brooksbank)

The UK coal industry was suddenly the largest public-owned corporation outside the Communist bloc - employing just under 700,000 workers across the UK – and needed to harmonise the views of politicians, miners, engineers, and the NCB, all of whom had differing visions.

Dr Curtis said: “One of the key things was that there was more of a consultative element to the process in the early years of nationalisation, in terms of how the industry was run – you had consultative committees.

“There were mechanisms by which the union could make its views known on any number of topics- there was a forum for discussion, to a degree that hadn’t existed before.”

Over time, though, this atmosphere diminished.

Some miners noted that those who had been managers or mine owners during privatisation made up a significant part of the NCB – “It was the same rugby team just wearing different jerseys,” one Rhondda miner allegedly complained.

The Aberfan Disaster left 116 children and 28 adults dead. (Picture source: Huw Evans Agency)

Along with bitter tragedies like the Aberfan Disaster and the explosion at Six Bells Colliery, Gwent, years of Conservative rule and the closure of unprofitable mines during the 1960s led to deepening resentment towards the NCB.

“The NUM certainly falls out of love with nationalisation, and colliery closures really drive that,” Dr Curtis added.

“It was perceived that they were turning the industry into state capitalism – there was a sense by that period that, fundamentally, there was still this master and servant dynamic.”

This discontent played out in the form of widespread striking in 1972, 1974, and finally, the year-long strike of 1984, which saw the NUM face off against Margaret Thatcher in an attempt to prevent further pit closures.

The closures went ahead, and in 1994, under Thatcher’s successor, John Major, the industry was put back into private hands.

The quick sale of the NCB’s assets and land has left a complicated legacy across the UK, and perhaps nowhere moreso than the south of Wales, where hundreds of unstable coal tips still dominate the landscape.