Britain First not authorised to use image of Crown
A breakaway group from the British National Party has been ordered to remove images of the Royal Crown from publicity material and merchandise.
Britain First did not get permission to use royal emblems on T-shirts and hoodies.
Organisations wanting to feature certain royal symbols have to contact the Royal Household.
Britain First failed to do so. Now the Cabinet Office has intervened, ordering the party not to use the crown.
The Royal Household has issued guidance showing three "conventional representations" of the Royal Crown that must not be used without permission.
But it says there is nothing to stop the use of other crown designs that do not resemble the Royal Crown.
The Cabinet Office - the government's link to the Royal Household - said it had written to Britain First, whose campaign slogan is Taking Our Country Back.
Asked what would happen if the party did not comply, a Cabinet Office spokesman refused to say what the next steps would be.
The Advertising Standards Authority has also ruled that the party should remove images of the Crown from its website.
It followed a complaint from an "internet user".
In a statement, the ASA said: "We understood from the Cabinet Office that the Lord Chamberlain's Office, responsible for authorising official use of the Royal Crown and Scottish Arms, had not granted permission for Britain First to use the royal emblems on their merchandising.
"The design on the clothing was clearly visible on the website pages and in the ad on Facebook and, because we had seen no evidence to show that Britain First was entitled to use the emblems, we considered that the images of the Royal Crown and Scottish Arms had been used without prior permission and therefore breach the Code."
The ASA wrote to Britain First about the issue but did not get a response.
Britain First leader Paul Golding told the BBC he was ignoring the ASA's ruling, describing the organisation as a "toothless, powerless quango".
Mr Golding said he had not received a letter from the Cabinet Office.
He insisted that the crown used by Britain First was not a royal crown which meant permission was not required.
In its "mission statement", Britain First says: "Our policies are pro-British, our approach is no-nonsense and our principles are not open to compromise.
"We love our people, our nation, our heritage and culture and will defend them at all times and no matter what odds we face."
A photo of the Queen and Duke of Edinburgh is featured next to the statement.
The party stood at this year's European elections, gaining 1.02% of the vote in Scotland and 0.9% in Wales - in the only two constituencies where it fielded candidates.