SENIOR SNP MPS are lining up behind left winger Tommy Sheppard in the party’s deputy leadership contest.

Westminster leader Ian Blackford had been tipped as the favourite, but faces a stiff challenge in a crowded field of candidates.

Last night, Livingston MP Hannah Bardell, was the latest politician to say she was giving "serious consideration" to standing.

Speaking to the Sunday Herald, Bardell said: “I appreciate the encouragement I’ve had in recent days and I’m giving it serious consideration. We’re in the fortunate position that there's no shortage of talent amongst my colleagues in the SNP. Like others considering, I have to weigh up how the job would be balanced with other aspects of my job as an MP.”

Other names saying they are considering standing are Westminster's Scottish affairs select committee chairman Peter Wishart and Glasgow Provan MSP Ivan McKee.

Sheppard is “giving seriously consideration" to standing, according to a source from his camp. However, the Edinburgh East MP has yet to formally declare. He said: "I'm thinking about it and have got a lot to weigh up. I'm in no hurry."

Glasgow Cathcart MSP James Dornan is the only politician to confirm his candidature. Kirsty Blackman, the SNP's deputy leader, is also expected to stand.

SNP frontbenchers such as health spokeswoman Dr Phillippa Whitford and justice spokeswoman Joanna Cherry have also been tipped as possible candidates. However, it's understood that both would be prepared to stand aside to give Sheppard a better chance of victory.

Whitford, a surgeon by profession, said she would be “happy” with Sheppard as deputy leader. Speaking about her own plans, she said: "I'm not going to make a decision anytime soon...I would still like to see Tommy do it."

Cherry, who is a QC, wants to see a left winger in post and would not press ahead with her own bid if Sheppard stood, SNP sources have said. Blackford has yet to confirm his bid, but there is already a backlash in the party against him.

An SNP source said some MPs were angered by what they saw as an assumption that Blackford would be the deputy, simply because like Robertson he is the Westminster leader.

In his resignation letter to Nicola Sturgeon, Robertson, who was the Moray MP until losing his seat, said he had been proud “to partner you as Westminster SNP Leader and as a parliamentarian representing a rural constituency.”

Blackford repeatedly said last week that he had no comment to make about the vacancy for deputy leader.

Transport minister Humza Yousaf and SNP MEP Alyn Smith have both ruled themselves out of the contest. Finance secretary Derek Mackay has yet to state his intentions.

Meanwhile, Dornan, said his party needed a more “working class” figure in the leadership. He said: "It's not a slight on Angus [Robertson], who was unique in terms of his reputation in the party. Angus was the prefect link between the two parties at Westminster and Holyrood. But I'm not convinced that's replaceable."

Dornan said the party had to clarify what the role of the deputy leader should be. The MSP said part of the job should be to help the SNP towards a second referendum.

Nominations for the deputy leadership of the SNP have yet to open. However, there is widespread speculation the winner will be announced at the next SNP conference in Aberdeen in June.