The Russian Revolution in 1917 started a wave of Communism feeling in working classes all along Europe. There were revolutions in Germany, Austria and Hungary, and in many countries the growth of mass Communist Parties. Britain in 1919 was part of this rising revolutionary wave.
In 1919, the miners put forward demands for a 30 percent wage increase, a reduction of working hours from eight to six per day, and nationalisation of the industry with joint control by owners and miners. The government had a bottomless appetite for coal to keep industry going; the threat of a miners' strike was national; two respected left wing union leaders-- Robert Smillie, president of the Miners' Federation of Great Britain, and Frank Hodges, its secretary-- were leading the agitation.
The miners were angry that the mines were privatised, with rich people who really did not care about miners, tending the mines, leading to a ridiculously high death rate where the focus was not safety, but money
You have to note the threat of a strike in the atmosphere. Already, various army units had mutinied and the police were angry. The Goverment really couldn't rely on them. If the miners started a strike, that would easily start a strike among other workers too, like railway men and transport workers who had banded together with miner's union in a Triple Alliance. This could have easily sparked a Communist revolution in Britain.
The Lloyd goverment promised a commision, the Sankey commision.
And so, on 3 March 1919, under the chairmanship of Sir John Sankey, the Commission thus set up began its deliberations. The Commission had to act with great dispatch since the miners were in no mood to be fobbed off with dilatory tactics.
The Commission issued its Report in two parts. In the first part, made public just 17 days after the Commission had been set up, it conceded the miners' demands for higher wages and a seven-hour day, and dangled the prospect of a six-hour day in the not too distant future. As to the question of the ownership of the miners, the Commission said nothing for the time being. The Miners' Federation accepted the concession, called off the proposed coal strike, and agreed to wait for the second part of the Report. In the latter, the Commission expressed itself, by a bare majority, in favour of the nationalisation of the mines, but the Government never accepted this part of the Report.
By the time the second part had been released, the momentum in the workers had died down, resulting in a Communist revolution looking unlikely. The Goverment agreed to the first part of the commission and tricked the miners so that the mines and their death rates were the same as before the strike.