LABOUR members supporting moves to topple Gordon Matheson as leader of Glasgow City Council are understood to have been warned by party bosses they risk disciplinary action

As the leader of the country's largest council faces unprecedented pressure to bring forward his exit, senior sources claim signatories to a motion calling for him to stand down are being told they could be breaching party rules and sanctioned.

It comes as several of the instigators of the campaign to have a new council leader in place within months continue to seek a showdown with Mr Matheson over his intentions.

Around 20 councillors, just under half of Mr Matheson's group, are said to have signed the motion. It includes some councillors previously close to the leader, as well as several in senior roles.

Sources close to Mr Matheson have said they believe the number to be "no more than 17" and have cast doubt on the identities of some of those said to be supporting regime change.

Confirming that several around the leader have also been contacting group members to persuade them not to sign, they have also accused signatories to the motion of having no unifying politics and fuelling disquiet amongst ordinary members.

But it has now emerged Scottish Labour's general secretary Brian Roy has been in contact with party whips on the council and others involved in the move to warn of the prospect of disciplinary action.

One senior source said: "Party officers in London have expressed interest and concern about the coverage surrounding Gordon and if people are trying to encourage discussions about his leadership.

"They've been in contact with officials in Scotland, asking to make contact with the Glasgow group.

"The discussions are about non-compliance and that anyone involved could be in breach of party rules.

"The concerns seems to be about the impact on the party leadership contest not the Labour group's future."

If he becomes deputy, Mr Matheson secures an automatic right to the top spot on Labour's Glasgow list for Holyrood next year, all but guaranteeing he would become an MSP.

But it has angered many Labour councillors, MSPS and 2016 candidates, who accuse Mr Matheson of hoping to catch a "lifeboat" to Holyrood.

For the past week his council leadership has been under more pressure than has been the case for several years.

He has since agreed to stand down in February, regardless of whether he became deputy or not.

The motion signed by the 20 or so councillors states: "We, the undersigned, hereby request that an extraordinary general meeting of the Glasgow City Council Labour Group is called on 10th August 2015 in order to discuss, agree and stabilise the leadership of the group well in advance of the upcoming elections to the Scottish Parliament in 2016 and to Glasgow City Council in 2017."

But one source close to Mr Matheson said: "Gordon has a very good chance of becoming deputy leader of the party in Scotland.

"How bad does it look if we throw him out before the result is even announced. He has said he will bring forward the annual general meeting by as much as he can and would go early in the New Year, allowing for a stable handover and giving enough time for two clear candidates to emerge."

Amongst those tipped to succeed Mr Matheson are former leader and Scottish minister Frank McAveety and rookie councillor and head of Fair Trade Scotland Martin Rhodes.

A Labour spokesman said the party did not comment on internal group matters.