"added description and sources"
Same-sex marriage: Civil unions (marriage rights) from Dec 5, 2005 to -0001.
The law still allows both same sex couples and straight couples to form civil unions as of December 2, 2019.
Sources: legislation.gov.uk/ukpga/20…
en.wikipedia.org/wiki/Marri…~:text=Sets%20out%20the%20short%20title,or%20Secretary%20of%20State%20appoints.
parliament.uk/about/living-…