Only the introduction of the 2010 Bribery Act made it "quite clear" to Sun journalists that they should not pay cash to public officials, The Sun corruption trial heard today.

Veteran reporter Jamie Pyatt said that News International circulated advice to journalists on how to abide by the Act, which stiffened corporate penalties for corruption."

It was quite clear payments could no longer be made to public officials," he told Kingston Crown Court."

Life was going to be very different working for the Sun."

In his third day in the witness box, Mr Pyatt – who has admitted the Sun made payments to two of his contacts; a Surrey Police constable and a Broadmoor healthcare assistant – said the cash payments system had been in operation at the Sun well before he joined the paper in 1987.

However Mr Pyatt, who referred to paying "police contacts" and "Broadmoor contacts" in emails to the Sun's news desk, said: "I never hand on heart believed I was doing anything wrong. I am not the sort of person who could commit a crime." He had been "shocked" when he was arrested by the Metropolitan Police on 4 November 2011 under the 1906 Prevention of Corruption Act. He told detectives, who had information about his cash payments: "I cannot understand how you came by that information."

News International's Management and Standards Committee had passed the information to police.

Mr Pyatt told the court: "Journalistic sources are sacrosanct and I couldn't believe that a company like News International would hand over a journalists sources for the purposes of investigation."

He said: "I was very shocked. I was read my rights. I was taken indoors. My boys were woken up. "I had always worked very closely with the police."

The reporter told the court: "I couldn't believe I had been handed over to the police by the company I have worked loyally for for 27 years."

In answer to questions from his lawyer Richard Kovalevsky QC, Mr Pyatt went on: "I felt completely betrayed by the company. "They were not prepared to protect me and they were not prepared to protect my sources."

At the end of his examination-in-chief, Mr Pyatt was asked by his lawyer about his attempts to uncover the truth about Jimmy Savile.

Mr Pyatt, who had previously told the jury that it had become increasingly difficult to obtain information from police through normal channels, had been trying to find out about the DJ's sex attacks on young women. He said: "I had managed to get the young women involved – three I believe, and a fourth was coming round – to give taped interviews of their ordeals at the hands of Jimmy Savile."

However, he added Savile had previously sued the Sun, meaning that his bosses told him he needed strong confirmation before running the story: "I was told their could only move forward if we had police assistance."

He asked for the police's co-operation, he told the court, but did not receive it.

Had he been able to find out the truth about Savile before he died, Mr Pyatt said, he did not believe "I would not be standing here."

He and five other past and present Sun executives and reporters deny conspiring to commit misconduct in a public office. The case continues.