LABOUR’S next leader is set to face their first test at the Trades Union Congress, according to the election timetable agreed by the party’s executive yesterday.

Voting will get underway in mid August and the new leader will be unveiled at a special conference on Saturday September 12 — a day before TUC congress begins in Brighton.

That means the winner is likely to give their first address as leader, aside from an acceptance speech, to thousands of workers representing 51 trade unions.

Blairite shadow ministers Chuka Umunna and Liz Kendall, the only official candidates so far, would be likely to receive a mixed reception from delegates.

The timetable was announced as the clamour among grassroots members for a left-wing candidate continued to grow.

An unofficial campaign was launched by the Socialist Campaign for Labour Victory yesterday to back miners’ MP Ian Lavery for the leadership.

The group’s statement said: “The left should put forward a candidate for Labour leader and in many ways Lavery is an excellent choice, as a former working-class activist and trade unionist from a region where Ukip is strong.”

Almost 700 people have so far signed up to the campaign’s Facebook page.

The Star revealed on Tuesday that Mr Lavery and shadow cabinet member Jon Trickett were tipped to stand after John McDonnell ruled himself out of a third leadership bid.

Neither have so far made a comment but talks are ongoing among left Labour MPs about who should stand.

Mr McDonnell told Tuesday night’s Left Platform meeting though that it is “highly unlikely” a left candidate could get the 35 nominations needed from fellow MPs.

He said: “We’ve done the calculations — myself and Jeremy (Corbyn) — of the number of potential nominations and we can’t get it above 19 or 20.”

The Socialist Campaign Group chair added that the focus should be on “making Labour a party of struggle again” rather than just an “electoral machine.”

But Labour member Mike Phipps said: “We need to have a candidate come forward now to make sure they’re on the TV with the other candidates making a different argument.”

Meanwhile, more than 1,200 have signed a petition calling for Ed Miliband to be reinstated as Labour leader.

lukejames@peoples-press.com