Mark Burgess, 68, started giving evidence at Portsmouth Crown Court where he denies 52 offences between 1976 and 2009.

‘(The complainant) says you were having a conversation about how far you could ejaculate and there were two or three others present,’ she said.

She said it was claimed there would be ‘a semi-circle so they would all be able to see’. Similar individual incidents with boys in the vestry were also alleged to have taken place.

Asked if any of these happened, Burgess said: ‘No, not at all.’

The same boy also said he used to visit Burgess at his garage where ‘oral sex would take place’ but Burgess said the boy ‘would not even know the existence of the garage’.

On another trip the boy was said to be ‘really homesick’ and came back to the dorm ‘tired’ before Burgess made his move.

‘You put your hands down his pants and unzipped his trousers before giving him oral sex. Did that happen?’ Ms Russell asked.

‘No,’ he replied.

On another occasion the boy swore at Burgess who was asked by Ms Russell if there was anything he had done to receive the abuse. ‘That was just the way he was made. He was a most unusual person,’ he said.

He went on to call the boy’s behaviour ‘unacceptable’ and branded him as ‘gobby’.

Fern Russell, defending, asked Burgess if he touched the boy. Burgess said: ‘No it’s a public place.’

Ms Russell said: ‘Is that the reason?’

Burgess said: ‘No. The reason is if you’re playing a piano people know you’re in there.’

Asked if he said ‘did you enjoy that?’ Burgess added: ‘No. Not at all.’

Ms Russell added: ‘Do you remember locking yourself in the vestry (with the complainant)?’

Burgess said: ‘No-one. Never.’

Further asked if Burgess promoted people within choirs unduly, he said: ‘I’d be answerable to people for that.’

He confirmed some students had visited the home he shared with his mother and father.

But he said ‘it would have been wrong’ to have younger students visit.

Burgess, of St Chad’s Avenue, Hilsea, denies 27 charges of indecent assault, 17 of gross indecency with a child, five of buggery, two of sexual activity with a child and one attempted indecent assault.

Jurors have heard the former Portsmouth City Boys School music teacher was a choirmaster at St John the Baptist Church in Westbourne, and at All Saints Church in Commercial Road.

The trial continues