A 73-year-old former Christian Brother has gone on trial in Galway charged with the sexual abuse of a young boy at St Joseph's Industrial School in Letterfrack during the 1960s.

The former inmate of Letterfrack, who is now 59, told the court he was sentenced to four years detention when he was nine years old for stealing a bicycle from outside a Dublin church.

He returned the bicycle later that day to his local garda station but was charged with its theft.

The man said he was the smallest boy in Letterfrack for many years and had been in the institution for two years before his alleged abuser arrived there.

He told the court he was abused two to three times every week from then, until he left the institution in April 1967.

The court heard that the Christian Brother nicknamed him "Tuppence" after telling him he was not worth tuppence.

The retired teacher has pleaded not guilty to six charges of indecent assault against the boy on dates between 30 August 1965 and 4 April 1967.

The trial began before a jury at Galway Circuit Criminal Court this morning and is expected to last two to three days.