Moves have been made to ensure a controversial probe, where the county council's Conservative administration was given permission to hunt through fellow Tory councillors' email logs, is never repeated.

Earlier this year, Dr Wendy Thomson, managing director of Norfolk County Council, sanctioned an investigation into who leaked an email about councillors' expenses.

It was led by Stuart Dark, Conservative councillor for Dersingham and a former senior Metropolitan Police officer. He is now chairman of the children's services committee.

The investigation was launched after the EDP ran an article based on information in an email sent by then county council leader Cliff Jordan to his fellow Conservative councillors, telling them not to reveal what they had spent their allowance increase on.

While the investigation into email logs did not lead to any sanctions against any members, opposition councillors criticised the probe - and the way the council's top officer had permitted it.

The Conservative group had given permission, but at a meeting of the council today a motion was tabled to tighten up council policies to prevent such an investigation happening again.

The motion, put forward by Labour's Steve Morphew and unanimously agreed, called for a group of councillors working on the council's constitution to add in wording to prevent such a probe happening again.

That will state that, other than if the monitoring officer is investigating an alleged code of conduct breach or law enforcement agencies are probing an allegation, all information about and contained in councillor emails should remain confidential.

For any other reason, written permission would need to be sought and given by councillors.

Mr Morphew said: 'I know one of the issues was that the Conservative group gave permission, but I think individuals, not the group, should be the ones to give permission.

'I'd like to see it properly examined and properly codified as part of the constitution.

'The aim of this motion is to try to ensure that what happened never happens again.'

Independent councillor Alexandra Kemp, who represents Clenchwarton and King's Lynn South, said it was important that people contacting councillors knew that information would not be compromised.

There could yet be exemptions because of Freedom Of Information Act or Data access requests, but the working group will consider that.