MSPs looking to oust Richard Leonard as Scottish Labour leader warned today that their push to topple him could end in court after the party’s secretary rejected the latest bid to have him removed.

Centrist members of Scottish Labour’s parliamentary group continued seeking a path to a leadership challenge after a letter from the rebel MSPs was dismissed by party officials. 

The group, which includes James Kelly and Daniel Johnson, argues that a fifth of MSPs no longer supporting Mr Leonard should be enough to permit a leadership election.

Their argument relies on an assumption that the Scottish Party “defers” to the UK rule book, which they claim would require only five MSPs to back their attempts. 

Rejecting the move, Scottish Labour general secretary Michael Sharpe said he was “not aware of any such precedent on this issue,” and that the election of a leader was a matter for the Scottish party.

But reports in the Times suggested that opponents of the leadership would consider a judicial review if the party refused to allow a challenge. 

A Scottish Labour spokesperson said: “The Scottish Labour rule book is not silent on the issue of leadership elections: it makes clear that ‘the leader and deputy leader of the Scottish Labour Party shall be elected according to the procedural rules set out by the Scottish Executive Committee (SEC).’

“For the avoidance of doubt, the UK Labour rule book also includes the exact same provision for the election of Scottish Labour’s leader and deputy leader.”

The latest attempt to oust Mr Leonard comes after Mr Kelly and Mr Johnson called on Mr Leonard to quit, alongside fellow MSPs Jenny Marra and Mark Griffin last week.

Those supporting Mr Leonard’s removal failed today to name a suitable successor, with Mr Johnson claiming they would first clarify the details of any leadership contest.

Speaking to BBC Scotland, he claimed it was “certainly highly questionable” that the leadership could not be challenged in this way. 

Asked about the prospect of a court challenge, Mr Johnson said: “It is certainly challengeable and we need to look at all our options.”

But a Labour source dismissed the idea, telling the Star: “This is the last throes of a failed coup.

“They wanted him out before Saturday’s SEC meeting and in that they will fail.”