National park bosses have issued an alert to community leaders across the North York Moors over Government proposals to allow barns, shops, offices and cafes across the highly protected area to be converted into homes without planning permission.

The extraordinary move by the North York Moors National Park Authority reflects leading officers’ level of concern for the landscapes and communities across the 554sq mile area if the proposed relaxation of the planning system outlined in a government consultation is approved.

The proposals which would allow existing barns and other rural buildings to be converted to up to ten houses per unit without the need to apply for planning permission.

The consultation also seeks views on allowing all existing commercial offices, shops and cafes in national parks to become houses through permitted development, also without the need to apply for planning permission.

As property values are the highest for residential uses, national park bosses are concerned the permitted development rights could be used by someone wanting to wind down a business, such as a post office or cafe, without going through the planning application process.

The Levelling Up and Regeneration Bill consultation states the justification to remove the requirement for planning permission to be granted to change the use of a property is to support growth “by providing certainty and removing the time and money needed to submit a planning application”.

The move follows the Yorkshire Dales National Park Authority chief executive David Butterworth describing the proposals as “bonkers”, saying they would “decimate” national park landscapes.

The North York Moors authority’s letter to parish councils ahead of the park authority considering its response to the consultation on Thursday features a withering assessment of the Government proposals, dubbing them “both “unnecessary and deeply harmful to the landscape, heritage and the economies of our national parks”.

The letter states: “Replacing historic barns with unrestricted housing especially in open, isolated and remote locations would change these historic landscapes for ever and create a sprawl of houses with associated infrastructure such as overhead lines and access roads in areas which Parliament has committed to protect as places of natural beauty and cultural heritage.

“This proposal will mean no occupancy conditions can be imposed and

could result in seasonally empty houses scattered across the landscape mostly bought up by wealthy residents from other parts of the country.

“For our rural village centres and lively towns, withdrawing the protection of planning to maintain their commercial use will likely result in loss to more profitable residential use and could mean the loss of many local services at the expense of more holiday and second homes in our villages.

“People will rightly ask why, in an area protected for its natural beauty planning permission is needed for minor developments such as a domestic side extension or a porch greater than three square metres and yet an agricultural business is able to develop up to ten houses in the open landscape without even the need to apply for planning permission.

“We think this disproportionate move will be deeply unpopular and bring the planning system into disrepute with a further loss of public confidence in planning.”

A spokesperson for the Department for Levelling Up, Housing and Communities said it would consider all responses to the consultation, including that from National Parks UK, before coming to a decision.

He added: “We have been clear that any developments must be beautiful and enhance the environment.”