Kate Osamor asked a judge for leniency for her son after he was found with £2,500 worth of drugs DANNY LAWSON/PA

A Labour MP could face a parliamentary inquiry for using House of Commons notepaper to plead with a judge not to jail her “beautiful son” for serious drug offences.

Kate Osamor stated her position at the time on Jeremy Corbyn’s front bench when she wrote to the judge who spared her son a jail term in October for possessing drugs including cocaine and ecstasy with intent to supply.

Her letter was released yesterday after the judge agreed with an application by The Times and other newspapers, which argued that the public interest demanded transparency in the sentencing process.

Ms Osamor wrote to the judge on House of Commons notepaper

Ms Osamor is understood to be facing a parliamentary standards investigation over her conduct and may have broken rules stating that official stationery is “provided only for…