A 17-year-old was hauled before the courts for buying a child’s train ticket – costing the taxpayer hundreds of pounds in court costs and legal aid – despite offering to pay a fine as soon as he was caught.

The youth, who cannot be named because he is under 18, admitted the offence and ended up walking away from Highbury Corner Youth Court with a £17.70 fine – just a fraction of the £80 on-the-spot penalty that could have settled the matter before it reached a judge.

The teenager was attempting to save “a couple of pounds” on a trip from his home in Bexleyheath to Camden Town by buying a child’s fare on April 19 this year, prosecutor Daniel Kavanagh said.

He was caught at Camden Town after staff noticed he was hesitant at the barriers and he was eventually arrested by British Transport Police (BTP).

District Judge Nina Tempia queried why the teenager was not issued with a fine. David Finney, acting for the youth, said: “It would appear that was not considered.”

The defence lawyer added that he was surprised the offence had come to court. The teenager’s father had immediately offered to pay a fine on the day, he said.

After the hearing last week, a spokesman for BTP said the case went to court because the defendant failed to attend an appointment with officers, where he was set to be cautioned.