Two prominent candidates have announced they are running for leadership of Britain's fractious right-wing U.K. Independence Party — both warning UKIP faces extinction if it doesn't change.

Suzanne Evans and Paul Nuttall declared their candidacies Sunday.

Evans, who has clashed with longtime leader Nigel Farage, said UKIP must shed its "toxic image" and move from the right to the "common-sense center."

Former Farage deputy Nuttall said he would be a unity candidate to save a party "looking over the edge of a political cliff."

UKIP was instrumental in getting Britain to hold a referendum on EU membership, which ended in a June 23 vote to leave the 28-nation bloc. The result was a political triumph for UKIP, but since gaining its long-sought goal the party has been torn by infighting.