A councillor sexually assaulted a baby then threatened to reveal naked photos of the child’s mother if she spoke out, a court heard.

Former stockbroker Mark McCarthy, from Worthing, laughed after indecently assaulting the boy in front of two witnesses, a jury was told.

He then told his alleged victim’s mother he would humiliate her by publishing intimate pictures of her in newspapers, She had called police after the 37-year-old, who was a Conservative member of Worthing Borough Council, allegedly abused the baby.

McCarthy, who has since quit the council and the Tory party, faces two counts of indecent assault on a child and making a threatening phone call with the intention of perverting the course of justice.

A jury at Oxford Crown Court heard yesterday that the boy’s mother was shocked when the councillor carried out the act on her baby.

She told the jury she had initially not thought of it as sexual abuse but later realised she was wrong and gave a statement to police.

However, before the trial got to court, McCarthy phoned her saying: “You are ****ed either way, darling, you really are.”

Alan Blake, prosecuting, told the jury the woman was the mother of a little boy who was less than a year old at the time.

Giving evidence, she told the jury she had seen McCarthy bend over and assault the baby.

The child’s mother said she had given a shocked laugh at the time but had only remonstrated with McCarthy when he repeated the bizarre assault a few weeks later.

She told him: “It’s wrong. Don’t you ever do that again.”

But he told her: “I only did it because it made you laugh the first time.”

She later received a silent phone call followed by a call from McCarthy himself, in which he told her he had naked pictures of her.

“He said he was going to publish the pictures of her in the papers to prove he was not a paedophile,” said the prosecutor.

The mother had been “angry, worried and intimidated” by the call.

Mr Blake said: “He (McCarthy) knew perfectly well that she was a witness and those calls were clearly intended to dissuade her from coming to court,” he said.

The woman told the jury she admitted getting angry with McCarthy and telling him: “You are sick. You are going to prison.”

“He told me he had those pictures but I knew that was not true as I have never done anything like that in front of anyone, particularly not in front of a camera,” she said.

The jury later heard from a woman who said she was an eyewitness to McCarthy’s alleged assault on the baby.

After the alleged assault, she said McCarthy thought it was funny. “He was laughing. We were very shocked,” she said.

Detective Constable Stuart May said that when McCarthy was interviewed he had made no comment but handed over a statement prepared with his solicitor, which denied the “vicious allegations”.

He was later charged with indecent assault and with witness intimidation because he allegedly telephoned the mother and threatened to publish pictures of her if she went to court.

McCarthy, of Offington Avenue, Worthing, denies two counts of indecent assault and one count of making a threatening phone call to the witness with the intention that justice be perverted or interfered with.

The trial continues.