A third lawmaker declared his candidacy to lead Britain's opposition Labour party on Wednesday, after the party ruled that its embattled chief Jeremy Corbyn can automatically appear on the ballot in a leadership contest.
Owen Smith said he can provide a "radical and credible" alternative to Corbyn and can lead Labour into government.
"I will stand in this election and I will do the decent thing and fight Jeremy Corbyn on the issues, just as he will do with me, and at the end of that I will stand behind whoever the leader is," Smith told BBC Radio 4's Today programme.
Angela Eagle formally announced her candidacy on Monday, after she rallied the required support of at least 20 per cent of Labour lawmakers in the British or European parliaments.
Labour's National Executive Committee ruled late Tuesday that Corbyn could stand automatically against Eagle without having to secure similar support.
Eagle launched her challenge to trade-union-backed Corbyn after repeatedly urging him to resign following a vote of no confidence by 170 of Labour's 231 members of parliament.
Corbyn, who has also seen most of his former shadow cabinet resign, won a leadership election in September with almost 60 per cent of the 422,000 votes from party members, beating three other candidates.