Scotland Yard detectives have been condemned as a “disgrace” and their investigation into alleged Tower Hamlets election fraud called a “whitewash” after a year-long probe unearthed no criminal activity.

The decision by Met Police that “there is insufficient evidence that criminal offences had been committed” comes almost a year after an election court exposed a culture of corruption and bribery at the Town Hall.

Background Mayor Lutfur Rahman found guilty of illegal practices, poll voided, Rahman banned

Mayor Lutfur Rahman was stripped of office, another councillor booted out and their party dissolved as the High Court heard evidence of irregular postal voting and intimidation at the polling booths.

The 200-page judgment did not specifically call on police to take action but the police established a Special Enquiry Team to investigation five new allegations as well as new material in relation to 47 original allegations that the case revealed. Its decision to let the matter rest was supported by the Crown Prosecution Service.

Cllr Peter Golds is quizzed by the media outside the High Court following the Election Court decision

Campaigners against corruption in the borough have frequently cited police indifference or inaction as fertile ground for the kind of intimidation and ballot fraud that had dogged elections in the borough. They are furious at the decision.

Andy Erlam was one of the petitioners who took Lutfur Rahman to court and he is still engaged in court action to recover his costs.

He said: “The Met police decision not to prosecute any of the offenders identified in the Tower Hamlets election court is outrageous.

“The Met has never properly followed up detailed allegations submitted by myself and many others. The police continue us to turn a blind eye in Tower Hamlets. The Met has protected Mr Rahman and co. and we will now consider taking private prosecutions. The Met decision is an utter disgrace.”

Disgraced: Lutfur Rahman trying to hide under a fishing hat as he arrives at the High Court during the election case

Isle of Dogs councillor Peter Golds, Tory Group leader, said the police should be “utterly ashamed” of their handling of the Tower Hamlets issue.

He said: “It took four brave people to risk their all to bring the election petition. It revealed extraordinary levels of corruption, yet the police do nothing – as they have repeatedly done in the past.

“Londoners who hope for free and fair elections have been failed by the MPS.”

The police said that the burden proof was higher and the rules of evidence more stringent in criminal cases than that acceptable in the election trail, a civil case.

Scotland Yard said: “The Metropolitan Police Service takes any allegations of electoral fraud or malpractice very seriously.

Read more High Court rejects claims Lutfur Rahman’s wife had financial interest in his property

“We will continue to work closely with the Electoral Commission, and local authorities, to ensure we play our part to protect the integrity of the electoral process in London.”

A spokesman for Tower Hamlets council said: “We have put in place tough and detailed measures to combat fraud, and our response to allegations of fraud has been independently recognised as both comprehensive and rapid.

“We are pleased that the review recognises our hard work and progress and the subsequent reduction in public concern around elections in the borough.”