A voter became suspicious when a council worker offered to “fold” and “post” his voting papers at a Limehouse polling station, a judge sitting at a special High Court hearing has heard.

Robert Cherry told how he feared that the votes he had cast during the local elections in May last year were at risk of being invalidated.

He appeared yesterday at the Election Court trial where Lutfur Rahman, independent mayor of Tower Hamlets - and leader of Tower Hamlets First (THF), has been accused of “electoral fraud”.

Mr Cherry said he had voted at a polling station in the Cyril Jackson school when a council employee offered to help.

“After completing my votes and preparing to post them in the different ballot boxes, an employee of Tower Hamlets offered to take, fold them, and post them for me,” he said. “I declined and posted my papers myself.”

Mr Cherry told election commissioner Richard Mawrey, who is sitting as a judge at the trial. that he had voted many times but had never had such an offer before.

“I felt it was inappropriate,” he said. “I believed it was a possibility that somebody might invalidate my vote either by marking with a pen or a tear in the paper.”

His comments came as Peter Golds, leader of the Conservative group on Tower Hamlets Council, spoke of concern at police forces around the country not responding to “electoral malpractice”.

Addressing the court, he said: “In my experience elections in [Tower Hamlets] are the least transparent, worst managed and corrupt I have seen in London.

“For over a decade electoral malpractice has been an ongoing problem in the borough ... masses of evidence has been sent to the police and either ignored or been subject to ‘cut and paste’ investigations.”

Former political adviser Andy Erlam is leading a group of four voters who have taken legal action against Mr Rahman. The group wants Mr Mawrey to declare the result of the May 2014 mayoral election, which saw Mr Rahman elected for a second term, void and order a re-run. Mr Rahman denies wrongdoing.

The hearing continues.