Under the headline "Queen Backs Brexit", the Sun quoted anonymous sources as saying the monarch during a lunch in 2011 told the then Deputy Prime Minister Nick Clegg that the EU was heading in the wrong direction.
The story which said that the queen "left no room for doubt about her passionate feelings over Europe," has infuriated the Buckingham Palace.
The palace has now complained to the press watchdog, Independent Press Standards Organization over the tabloid’s reporting. In a letter, the palace said the story had breached a prohibition in the Editors' Code of Practice against "inaccurate, misleading or distorted information or images."
According to the Sun’s report, the queen made her opinions to Clegg and it stands by the story which is based on “two impeccable sources”. But the Liberal Democrat leader has denied the claim. Clegg said the notion that the queen expressed a strongly anti-Brussels view is ‘nonsense’.
Under the British norm, the queen is prohibited from taking sides in political debates and rarely makes her personal views public.
The report has caused a row as British politicians remained busy debating Britain's EU membership ahead of a June 23 referendum on whether to remain in the 28-nation bloc.