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 until the council was merged into Cornwall Council, a unitary authority.[1]
She subsequently stood, unsuccessfully, for Parliament on a number of occasions. At the 2010 general election, Jenkin stood in Camborne and Redruth, taking 775 votes, coming fifth of seven candidates.[2] At the 2015 general election, Jenkin again stood in Camborne and Redruth, taking 897 votes, giving her the last place of six candidates standing, but increasing her vote total and also her percentage of votes cast (+0.2%).
Jenkin has two children, who were brought up speaking Cornish as their first language.[1] She is a member of Akademi Kernewek, the official body responsible for corpus planning for the Cornish language,[11] serving on the terminology panel and the Cornish language place-names and signage panel.[12]