British Go Congress
Starting in Oxford in 1968 it has moved around Great Britain over the next fifty years. See https://www.britgo.org/history/bgc.html.
The main Go tournament is the two-day British Open. A variety of top UK and foreign players have won it over the years, Matthew Macfadyen being the top winner with ten victories. The top players also compete for points towards selection for the Korean Prime Minister's Cup.
The weekend also hosts the Annual General Meeting of the British Go Association.