Nigel Farage has withdrawn his resignation as leader of Ukip four days after standing down when he failed to win his target seat of South Thanet in the general election.

The party said it had refused to accept Farage's decision to go and his recommendation that Suzanne Evans, his deputy, be appointed as a caretaker leader.

Farage had said for weeks that he would step down if he did not become an MP, arguing that it was not credible to lead the party without being in the Commons. After losing by about 2,000 votes to the Conservatives' Craig Mackinlay, the Ukip leader said he would stick to his pledge as a man of his word.

He said he was happier than he had been for a long time and planned to have a rest by going fishing and spending time with his family. But he left the door open for a return, saying he could put his name forward when Ukip picked a new leader in September.

After a weekend off, Farage was back on the airwaves on Monday telling Good Morning Britain: "I said I would step down; I've stepped down … There will then be a contest in September for the leader of Ukip. I cannot say whether I will or will not stand. I have absolutely – at this moment in time – no idea."