THE editor of the Daily Mail was aware the newspaper was using search agencies, but not the extent to which they were doing so, he told the inquiry into press standards.

Paul Dacre, editor-in-chief of Associated Newspapers, which publishes the Daily Mail and the Mail on Sunday, told the Leveson Inquiry that using private detectives to access information used to be commonplace in the newspaper industry.

The inquiry has previously heard from Mail on Sunday editor Peter Wright the paper continued using private detective Steve Whittamore for 18 months after he was the target of a raid during in an investigation into the unlawful trade of personal information.

Whittamore was convicted of illegally accessing data in April 2005. Mr Dacre, the longest-serving Fleet Street editor, said yesterday: "We wrote to Mr Whittamore and said could he give us an assurance he was acting within the law.

"In 2007 we brought the shutters down and absolutely banned the use of all these ... of Whittamore inquiry agencies."

Mr Dacre said that "everybody, every newspaper" had been using Whittamore at one stage. He admitted he was aware the Daily Mail had been using Whittamore before 2006.

He said: "We didn't realise what they were doing was illegal. There was a very hazy understanding of how the Data Protection Act worked and this was seen as a very quick way of obtaining phone numbers and addresses to corroborate stories."

Mr Dacre also called for a new system of accrediting journalists to act as an "essential kite mark" for standards. He told the Leveson Inquiry "the existing press cards don't mean much".

He also argued there should be a new self-regulatory body, standing alongside the Press Complaints Commission (PCC), to deal with press standards.

He said: "I do believe there is an opportunity to build on the existing haphazard press card system.

"There are 17 bodies at the moment providing these cards. By transforming it into an essential kite mark for ethical and proper journalism, the key would be to make the cards available only to members of print newsgathering organisations or magazines who have signed up to the new body and its code."

He said journalists would then be at risk of having their cards removed, cancelled in a similar way to doctors who are struck off by the General Medical Council.

Mr Dacre also defended a story about stabbed mother Abigail Witchalls in the Daily Mail.

Last week the mother of Ms Witchalls, who was left paralysed after being stabbed in front of her son in 2005, told the inquiry about media intrusion following the attack.

One example given was a Daily Mail article in November 2005 linking Mrs Witchalls's attack to an assault suffered by her vulnerable brother some years earlier.

However, Mr Dacre said: "To my mind this is a story and a feature handled with superb sensitivity."

He also defended Daily Mail columnist Jan Moir for a controversial opinion piece she wrote following the death of Boyzone singer Stephen Gately in 2009.

Thousands of complaints were made to the PCC about the article due to what counsel to the inquiry Robert Jay, QC, referred to as "a cack-handed attempt to link this man's death, which was due to natural causes, to his particular lifestyle".

Mr Dacre said: "My view is that when the furore broke, perhaps the timing was a little regrettable.

"I think the piece, the column, could have benefited from a little judicious sub-editing."

He later defended an Associated Newspapers' description of actor Hugh Grant's allegations about phone hacking as "mendacious smears".

''