SCOTTISH Labour's Jackie Baillie has become the runaway favourite to become the party's next deputy leader after it emerged her rival will be facing disciplinary action for breaking the party whip.

Glasgow councillor Matt Kerr reportedly walked out of Thursday night's budget vote at the City Chambers saying he could not vote for any party's proposals – including his own.

Kerr refused to back Labour's budget plans after saying councillors needed to stand up to central government and fight cuts.

It is understood that all Glasgow Labour councillors have now been informed of the action taken against him.

The party's city finance spokesman, Malcolm Cunning, later said he was "hugely disappointed" and that refusing to back Labour's proposals was breaking the group whip.

Kerr said on Twitter that he "yesterday announced that [he] could not vote for any cuts budget being proposed for the city that [he represents]. [He has] had enough, this city has had enough and we owe it to the people we represent to put up a fight".

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But Councillor Cunning responded on the platform, saying: "You broke the group whip, indulged in personal grandstanding and gifted the SNP an attack line before walking out and leaving your Labour colleagues to deal with the consequences."

Glasgow Labour chair Marie McGarrity has said that she has switched her support in the deputy leadership race from Kerr to Baillie as a result. 

She said: “Leadership is not walking out on your colleagues or trying to throw them under a bus. That's not unity. I nominated Matt Kerr, but through this contest it has become clear that Jackie Baillie is the real change candidate. I will be voting for her."

Kerr said: "I have not been notified [of disciplinary action] but it is also not unexpected.

“Declining to support a Labour Group decision is not something I did lightly, but each of us has to make a stand against the SNP cuts at some point.

“I could not have in all conscience voted for any of the budgets proposed in the Chamber yesterday. I have had enough, this city has had enough and we owe it to the people we represent to put up a fight.

“I hope my action generates debate throughout Labour in Scotland."