A journalist who was jailed for phone hacking-related offences in 2007 has told the Old Bailey that the phone hacking of royal aides at News of the World went further than he had previously admitted.

Clive Goodman was convicted of phone hacking-related offences which occurred between 1 November 2005 and 9 August 2006.

However, the jury in the phone hacking trial on Monday heard that he had also hacked royal aides in the months preceding this.

Goodman told jurors he had hacked the messages of Mark Dyer, an equerry to Prince William and Prince Harry, in September 2005 and that in October 2005 he had also snooped on the messages of Jamie Lowther Pinkerton, private secretary to the princes.

Months previously, in January 2005, Goodman says he had hacked the phone of Helen Aspery, who was at the time the personal secretary to the two princes.

"You were in fact hacking these three people, before November 2005 and they included Mr Dyer who was not part of the original case in 2006/2007," said David Spens, counsel for Goodman. The former NoW journalist replied: "Yes."

Goodman also admitted that he hacked the phone of Tom Parker Bowles, the son of the Duchess of Cornwall.

He got the voicemail numbers and the pin numbers for various royal aides from Glenn Mulcaire and Greg Miskiw, both former News of the World colleagues who have already pleaded guilty to hacking.

Goodman has not been charged with phone hacking offences but others in the trial including the News of the World's former editors Andy Coulson and Rebekah Brooks have been charged with conspiring with Mulcaire and Goodman and persons unknown to unlawfully intercept telephone voicemails.

Coulson and Brooks deny the charge.

The trial continues.