The Tory Party's Parliamentary candidate for Watford, who quit following his arrest by officers probing a three-year hate campaign, has now been told he should stand down as a councillor.

Yesterday, the Watford Observer exclusively revealed Ian Oakley had been arrested and then bailed by police investigating the harassment of several Liberal Democrat councillors in the town.

Mr Oakley was arrested on Friday and a Conservative spokesman last night confirmed he had stood down as the party’s parliamentary candidate for Watford.

Now there have been calls for Mr Oakley to stand down as a councillor in Northwood.

The police investigation, nicknamed Operation Tuition, has been coordinated by Hertfordshire Constabulary's major crime task force.

The allegations relate to the sustained harassment of Liberal Democrats in the town, some of whom have suffered vandalism to their personal property and received malicious phone calls.

Several councillors have had abuse scratched into their cars and their tyres slashed, while others have had vile graffiti daubed close to their home.

Some councillors have even had pornography sent to their houses.

Nascot councillor Mark Watkin has also been the victim of a vicious poison pen letter campaign that made unfounded sexual allegations about him.

Police yesterday confirmed a 31-year-old man had been arrested in relation to the incident.

Mr Oakley has not been charged and is now on police bail pending further enquiries.

Calls for Mr Oakley to resign his Northwood seat have been led by Councillor Mike Cox, leader of Hillingdon Council's Lib Dems.

He said: "If he's taken the decision to resign from Watford then he should certainly resign from Hillingdon where he has far more responsibility for direct relations with the public."