The file comprises election addresses, posters etc distributed by Phil Williams' campaign for Plaid Cymru in the 1968 Caerphilly by-election, along with copies of newspaper articles and the addresses of Fred Evans' (Labour) and Robert Williams (Conservative).

The archive comprises election ephemera, including election addresses, posters, drafts of election material, mostly for Plaid Cymru candidates for UK Parliament and local elections, along with some ephemera related to anti-nuclear weapons and anti-nuclear power campaigns and Plaid Cymru publications.