Kirkwood Homes has built a sales and marketing cabin to support its controversial development of 16 homes at Viewhill Farm on the north east fringe of Culloden Battlefield.
It applied for retrospective planning permission for the cabin and car park, which sit in the Culloden Muir Conservation Area, but that application was turned down last December.
Historic Environment Scotland said the hut had “some impact” on the views of the battlefield, where Jacobites met government soldiers in the last pitched battle on British soil in April 1746.
Despite the breach of planning rules, no action has been taken to take the hut down - with Highland Council now considering its next step.
A spokeswoman for Highland Council said: “The retrospective application for the unauthorised sales cabin was refused for failure to supply the information requested to properly assess the impact on road users.
“The Council is in the process of considering the best course of action to resolve this breach of planning control.”
The site is to the east side of Culloden Moor and 110 metres to the north east of the official battlefield boundary.
HES said any adverse impacts on the significance on the battlefield were likely to be limited.
It also said the hut was to be in place for two years with impact on the battlefield therefore temporary.
As a result, HES did not object to the hut being built although it stressed its position should not be taken as support for the proposal.
Councillor Andrew Jarvie, who represents Inverness South and who has been involved in planning decisions relating to the site, said: “It is really quite annoying. I would expect the developer to comply with the rules and to have removed the hut. It was refused planning permission for the hut almost two months ago and it is still there.”
Kirkwood Homes has been approached for a comment.