in the election of Gwynfor Evans, the first ever Plaid Cymru M.P. The contest was caused by the death of Lady Megan Lloyd George, Labour (and former Liberal) MP and daughter of David, 1st Earl Lloyd George of Dwyfor. This was followed by two further by-elections in Rhondda West in 1967 and Caerphilly in 1968, in which the party achieved massive swings of 30% and 40% respectively, coming within a whisker of victory as both also won a higher proportion of the vote then it had won in Carmarthen. The results were caused partly by an anti-Labour backlash. However, in Carmarthen particularly, Plaid Cymru also successfully depicted Labour's policies as a threat to the viability of small Welsh communities. Expectations in coal mining communities that the Wilson government would halt the long-term decline in their industry had been dashed by a significant downward revision of coal production estimates. Welsh Language Act 1967 With Plaid Cymru's electoral successes the issue of devolution was back on the national political agenda, wrote Dr Davies. A Plaid Cymru under Evans and a Labour party influenced by Gwilym Prys Davies (Gwilym Prys Davies had published a Labour pamphlet calling for a National Assembly of Wales in 1963) and James Griffiths, the argument "in favour of a political system in Wales more answerable to the electorate" was plausible. But by 1967 Labour retreated from endorsing home rule mainly because of the open hostility expressed by other Welsh Labour MPs to anything "which could be interpreted as a concession to nationalism", and because of opposition by the Secretary of State for Scotland, who was responding to a growth of Scottish nationalism. By 1967 the Welsh Language Act was passed, giving some legal protection for the use of Welsh in official government business. The Act was based on the Hughes Parry report, published in 1965, which advocated equal validity for Welsh in speech and in written documents, both in the courts and in public administration in Wales. However the Act did not include all the Hughes Parry report's recommendations. Prior to the Act, only the English language could be spoken at government and court proceedings. '79 Yes Campaign; Hunger Strike for S4C See also 1979 Welsh devolution referendum, S4C, Hunger strike In the 1970 General Election Plaid Cymru contested every seat in Wales for the first time and its vote share surged from 4.5% in 1966 to 11.5%.