A teacher friend of jailed Jeremy Forrest has said the 31-year-old “crossed the boundary” with his schoolgirl lover when they started tweeting one another.

Speaking on Channel 4’s Sexting Teacher on Tuesday night, Benedict Beaumont, of Brighton, said: “That is a boundary teachers know they’re not supposed to cross.”

Forrest, previously a maths teacher at Bishop Bell C of E School in Eastbourne, was jailed last year after being convicted of child abduction and sex offences.

Forrest, of Ringmer, near Lewes, was jailed for five-and-a-half years at Lewes Crown Court.