A man with learning difficulties will be the first British person to have a vasectomy on the orders of a judge because it is "in his best interests".

The 36-year-old man, known only as DE, already has a young son with his girlfriend, who also has learning difficulties, and has said he does not want another child.

Judge Justice Eleanor King, sitting in the Court of Protection in London, has now ruled sterilisation could take place as having another child would cause him "psychological harm". DE does not have the mental capacity to use contraception.

The Court of Protection previously heard how the birth of the man's son in 2010 had caused him anxiety and left him in "absolute turmoil". The court heard how if the couple had another child, it would be "inevitable" that it would be taken into care and cause them further distress.

The decision whether to allow DE to have a vasectomy had to be made by a judge, as he does not have the mental capacity to make a decision on whether or not to undergo a vasectomy or to consent to this procedure.

Angus Moon QC, appointed to represent DE, said this "truly exceptional case" was not a case of eugenics or a man being given a vasectomy against his will.

He said there is "compelling" evidence he does want to be sterilised to stop him having another child with his girlfriend of more than 10 years.

DE's parents fear that his girlfriend may want another child and that he would be "the only candidate" to be the father.

The court heard that DE did value his relationship with his son and is allowed to play with him for up to an hour a day.

This is only the second time an application has been made for the sterilisation of a man. The first, involving a man with Down's Syndrome, was refused in 1999.