Jenkin is the daughter of Richard and Ann Jenkin, key figures in Cornish nationalist political party Mebyon Kernow. She studied plant bioscience at Cardiff University and the University of Cambridge, and worked at a local conservation charity.
In 1990, she was elected as leader of Mebyon Kernow, then at a low ebb. She served until 1997, focusing on reviving the party's electoral performance. She stood as the party's candidate for Cornwall and West Plymouth at the 1994 European election, taking 1.5% of the vote. Soon after, she was elected to Kerrier District Council, representing the Crowan district. She has subsequently stood for Parliament on a number of occasions. At the 2010 UK general election, she stood in Camborne and Redruth, taking 775 votes. She was elected to Cornwall Council in a 2011 by-election, representing the Wendron district.
Jenkin is a lecturer at the Camborne School of Mines, where she has undertaken studies into Japanese knotweed, She is also a bard of the Gorsedh Kernow, has served as Cornwall's Great Trees Officer, and chairs the Cornish Language Fellowship. Jenkin has two children, who were brought up speaking Cornish as their first language.
- Bernard Deacon, Dick Cole and Garry Tregidga, Mebyon Kernow and Cornish nationalism, p.132
- "MK downcast following vote disappointment", Western Morning News, 12 May 2010
- "Mebyon Kernow triumph in Wendron election", Falmouth Packet, 25 November 2011
- "Eden 'weeds out' invasive plant", BBC News, 10 February 2002
- "County's new 'great' tree project ", BBC News, 20 September 2008
- "Language fellowship calls for more 'Cornish pride'", BBC News, 7 April 2011
|Party political offices|
|Leader of Mebyon Kernow