Council staff in Enfield were sent in to take down St George's flags and bunting at a polling station after fears that it could act as 'a dog whistle for the Leave campaign'.
The display was left up after the members of the Mayfield Athletic Club in Palmers Green had been watching Euro football matches.
There was also a large TV showing news programmes at the club house.
One voter said it 'looked like an EDL rally'.
The Electoral Commission said the flags and keeping televisions on did not breach any restrictions, but added: 'We have got in touch with Enfield Council to alert them and advise that it would best to take the flags down to prevent further concern by electors.'
A spokesperson added: 'Though we would advise against it and have already spoken to Enfield about this as there is a danger that something on the TV could be seen as promoting one side or the other.'
Enfield Council said the flags and bunting had been promptly removed.