Republican Party (United States) | Democratic Party (United States) | Ireland | Northern Ireland | Republic of Ireland | Australian Labor Party | Democratic Party | Liberal Party of Canada | United Kingdom of Great Britain and Ireland | Liberal Party of Australia | Republican Party | Liberal Party (UK) | Social Democratic Party of Germany | Liberal Party | Nazi Party | New Democratic Party | Progressive Conservative Party of Canada | Democratic-Republican Party | Northern Territory | Green Party | Democratic-Republican Party (United States) | Social Democratic Party | Progressive Conservative Party of Ontario | Conservative Party of Canada | Ontario Liberal Party | Communist Party | Communist Party of China | political party | Socialist Party | Republican Party (U.S.) |
His grandson, the fourth Baron, was a member of the Northern Ireland Assembly for the Alliance Party.
He is one of a number of high profile Ulster Unionist moderates who have left the party along with Harry Hamilton and Paula Bradshaw, who both joined the Alliance Party of Northern Ireland, and Trevor Ringland, who joined the NI Conservatives.
The Alliance Party of Northern Ireland stood Clark-Glass as their candidate for the Northern Ireland constituency in the European Parliament election in 1994, hoping that she would emulate the success of Mary Robinson in the Irish presidential election in 1990.
The sole exception, Stratton Mills, left the UUP and continued to take the whip for a further year, before joining the Alliance Party of Northern Ireland.