A General Election blunder in Hounslow may have dissuaded some people from voting, a watchdog has concluded.

Around 3,000 electors in Bedfont, within the constituency of Feltham & Heston, were sent polling cards directing them to the wrong station in May.

Hounslow Council officers hand-delivered letters to affected households once they discovered the error, as voters nationwide hit the polls on the morning of May 7, and laid on buses between the two polling stations.

But the Electoral Commission ruled the mix-up meant the performance of returning officer (RO) Mary Harpley, chief executive of Hounslow Council, was not up to scratch.

She was one of 24 returning officers - the people overseeing voting in their district and declaring the results - who failed to make the grade in the elections watchdog's assessment, published on Wednesday (July 15).

"While the RO put in place immediate actions to minimise the impact of the error on voters, including providing transportation for those affected to their correct polling station, the error may have dissuaded some electors from voting by requiring them to travel to a different polling location," the commission concluded.

"The impact of this error may have also caused significant voter confusion. In addition, the error could have affected the confidence of those standing for election in the management of the process as a whole."

The commission said returning officers who failed to meet its performance standards should take all necessary steps to prevent the issue recurring.

Hounslow Council leader Steve Curran assured voters the error had already been investigated and new measures were in place to avoid a repeat.

"We accept the assessment findings and welcome the role of the Electoral Commission which works to ensure that elections are held to the highest democratic standards," he said.

"I can assure the electorate that we've already investigated the poll card printing error and have put in place new measures which mean the likelihood of the same mistake happening again is minimal.

"I'm confident that elections held in Hounslow are soundly run and fair."

Labour MP Seema Malhotra retained the seat of Feltham & Heston with a majority of 11,463.