Prince Charles is set to convert his grandmother’s beloved summer retreat in the Scottish Highlands into a bed and breakfast guest house, and it’ll start welcoming members of the public from April next year.

The stables and granary at the Castle of Mey will be transformed into 10 luxury guest rooms. The Prince’s passion for sustainability is at the forefront of the project, with the accommodation using local materials and rooms fitted with modern eco-heating.

The castle holds a special place in the Prince’s heart; it belonged to the late Queen Mother from 1952 until 1996, when she endowed it to the Castle of Mey Trust.

The castle is located in Caithness in northern Scotland. After its purchase, the Queen Mother spent the first two years restoring both it and its gardens. She would escape London for the castle’s relaxed surroundings every August and October.

The Queen Mother opened the gardens for three days each year in aid of Scotland’s Gardens Scheme. Following her death in 2002, Prince Charles became actively involved in maintaining the castle, visiting the property each August and continuing the tradition of public viewings.

“His Royal Highness is trying to keep the castle going in his grandmother’s memory, driving the place forward and [giving] it a great future,” says Kenneth Dunsmuir, executive director of the Prince’s foundation.

“It was nearly a ruin before the Queen Mother saved it, and I think she would have been so keen to see this project,” he continued.

Special reminders of the Prince’s grandmother will be included throughout the bed and breakfast, with her ER motif engraved in the dining room skylight and her portraits hung across the walls.

Prince Charles plans to be hands-on throughout the design process, selecting colours, fabrics, furniture and even lighting styles. He will have the final say on every major aspect of the development, believing it’s the finer details that will really make it special.

It’s estimated a night’s accommodation will cost £160 (around A$280), and guests will enjoy dinner and breakfast made with local ingredients.

If the project is successful, there are plans to also use the castle and granary as a wedding venue.