He stayed in the post until December 1979; it was a difficult year for the party, which had faced defeat in the Welsh devolution referendum and the loss of Gwynfor Evans' seat in the general election.

In July 1979 he collaborated with Gareth Miles to publish Socialism for the Welsh People,[6][7] a pamphlet which was critical of Plaid Cymru for its "opportunism"[8] and alleged subservience to the British state.

[10] During George Galloway's attempt to be selected as the Labour candidate for Rhondda in the 1983 general election, Griffiths brought him along to events and introduced him to local people.

The WSRM was investigated by the police in relation to a bombing campaign and several of its members were arrested, including Robert Griffiths.

In 2016, Griffiths was unveiled as the chair of Left Leave, a campaign for the United Kingdom's withdrawal from the European Union.

European Parliament In the 1994 election, he stood on behalf of the Communist Party in the single-member South Wales Central constituency, winning 1,073 votes or 0.6% of the total.