A formal bullying complaint has reportedly been filed against former Commons Speaker John Bercow by a peer who served as his most senior official.

Lord Lisvane has handed a dossier of allegations to the Parliamentary Commissioner for Standards, according to The Times.

Mr Bercow, who is chancellor of Essex University, dismissed the claims as having come at a “curious” time, with suggestions he may be in line for a peerage.

The document is said to accuse Mr Bercow of having bullied and humiliated staff.

Mr Bercow has consistently denied allegations of bullying in the past.

In a statement he said: “During the five years that we worked together, Lord Lisvane had ample opportunity to raise any accusations of bullying with me.

“At no stage did he do so, even though he became Clerk of the House - the most senior official. The timing of this intervention is curious.”