Anthony Weiner, the former US congressman and New York mayoral candidate, has asked a judge for leniency when he is sentenced later this month for "sexting" an underage girl.

Mr Weiner admitted in May to sending sexually explicit messages to the 15-year-old from North Carolina.

In asking for Mr Weiner to avoid jail – and receive probation instead – his lawyers described his behaviour as “inexcusable”, but pointed to his “remarkable progress” in the treatment for his “sickness”.

Court documents read: “A term of imprisonment would bring Anthony’s indisputably successful treatment for the sickness underlying his crime to an immediate and complete halt.”

Writing separately to the judge, 53-year-old Mr Weiner said his string of scandals “crushed the aspirations” of his wife, Huma Abedin, a former advisor to presidential candidate Hillary Clinton.

Mr Weiner, who served as a congressman for New York between 1999 and 2011, faces a sentence of up to ten years in prison.

He will be ordered to register as a sex offender, regardless of his sentence.