A News International “private wire” phone line attempted to hack the voicemails of two senior royal aides hundreds of times in less than a year, a British court has heard.

The mobile phones of the right-hand men to the Prince of Wales, the Duke of Cambridge and Prince Harry were targeted by the line hundreds of times between October 26, 2005 and August 5, 2006, the Old Bailey heard.

The private wire, which allowed desk-based landlines to route calls through a mobile number, tried to access the voicemail of Jamie Lowther-Pinkerton, private secretary to William and Harry, 416 times and attempted to hack the phone of Mark Dyer, former private secretary to Charles, 296 times, it was alleged.

Both men have close personal ties to the royal family.

Lowther-Pinkerton, who stood aside from his full time roll as private secretary last year but still works with William, Harry and the Duchess of Cambridge, is so close to the family he was appointed godfather to Prince George earlier this year.

And Dyer, former equerry of Charles, was appointed the Prince of Wales’ private secretary with responsibility for William and Harry in the eight years following the death of their mother Diana, Princess of Wales.

The private wire also tried to intercept the phone messages of former culture secretary Tessa Jowell, former glamour model Katie Price, rival journalists at the Mail on Sunday and former News of the World deputy editor Neil Wallis, the trial of several former News International employees has heard.

Jurors were shown a document detailing the alleged hacking attempts.

The log showed 850 calls from the private wire to the phone numbers or voicemails.