REBECCA Long-Bailey will pledge to back workers and trade unions in every strike and dispute "no questions asked" if she succeeds in becoming Labour leader.

The Shadow Business Secretary said the party's path back to power after its worst General Election defeat since 1935 was by "rebuilding" the trade union movement.

She told a rally in Sheffield that the next leader must be "as comfortable on the picket line as at the dispatch box" and commit to giving workers a "right to unplug" from emails and calls outside of work hours.

"As leader, I'll put trade unions at the heart of Labour's path to power and back workers in every dispute,” Ms Long-Bailer declared.

Labour would "back workers in every dispute and strike against unfair, exploitative and unjust employers" under her leadership.

And she insisted “standing on the side of workers and trade unions, no questions asked, is going to be crucial in standing up to this reactionary Conservative Government".

Her speech came as Ian Murray, the party’s only Scottish MP, successfully made it onto the final ballot after gaining enough support from local parties.

The Edinburgh MP said: “I’m extremely grateful to ordinary Labour members across England, Scotland and Wales who have backed me for deputy leader. Grassroots members up and down the country have chosen to put change on the ballot paper.”

Ms Long-Bailey explained the Labour Party was the parliamentary wing of the whole Labour and trade union movement and that its path to power was in “rebuilding it".

She said she planned to commission a trade union recruitment plan in the party’s historic heartlands to win back support and to do more to "sweep away" anti-trade union laws.

Although the Salford MP is seen as the current leadership's favoured candidate, it appears she is facing an uphill battle to convince the membership to vote for her.

Polls have regularly been suggesting that Keir Starmer, the Shadow Brexit Secretary, is likely to come out on top in the ballot of members and supporters for the four-candidate race.

An Ipsos Mori study released on Thursday put Ms Long-Bailey in last place when 1,001 voters were asked if she had what it took to be Prime Minister.

She also trailed in last place - with Sir Keir on top, Lisa Nandy second and Emily Thornberry third - when Labour supporters were asked the same question.

One policy she hoped would be popular with the wider public was a proposal for a law to give workers the right not to be contacted outside of normal working hours in order to end the "24/7 work culture".

While her campaign team gave few details, a "right to disconnect" in France obliges organisations with more than 50 workers to define employees' rights to ignore their mobiles.

On Saturday, the party hustings moves to Nottingham, while on Sunday it is in Dudley. The Scottish hustings in Glasgow takes place next Saturday. Mr Corbyn's successor will be announced at a special conference in London on April 4.