David Makali has resigned as a member and Secretary General of the Labour Party of Kenya.
The former journalist handed in his resignation letter to LPK chairperson Julia Ojiambo on Monday.
"I thank you for the chance to do what we did and for your support in rebuilding and re-branding the party during the six months period I served," he said.
"I wish you and the party success in your future endeavours," he continued, adding he will be available to assist with the transition.
Makali's rivalry with LPK boss Ababu Namwamba began after he was kicked out of the party over links with Opposition leader Raila Odinga.
He reportedly told the party's NEC meeting that he has had several meetings with Raila who indicated his willingness to work with Ababu, a move that was not received well with the party.