Boutique hotel operator City & Country Hotels has revealed plans to open its fifth UK property next year.

The Langley, in Iver, Buckinghamshire, will be located on the former estate of the Duke of Marlborough and will occupy two buildings – the duke’s historic mansion and a Grade II-listed 18th century building, formerly used as stables and a brewhouse. The buildings are currently undergoing an extensive, multi-million-pound renovation under the guidance of interior design company Dennis Irvine Studio.

Facilities at the 41-bedroom hotel will include a large, 25,000sq ft (2,322sq m) luxury spa, offering eight large treatment rooms, an expansive VIP suite with dip pools, as well as a women-only thermal area.

There is also a health club created in partnership with personal trainer Matt Roberts, featuring a range of innovative fitness technology and equipment including a cryotherapy centre.

Roberts has also devised a programme of outdoor exercise classes suitable for the hotel’s landscaped gardens, which were designed in the 18th century by renowned landscape architect ‘Capability’ Brown.

The hotel is owned and will be managed by City & Country Hotels, which owns four other hotels – The Wellesley, Wyck Hill House, The Royal Hotel Cardiff and Nr 10 in Manchester – and The Wellesley MY luxury yachts.

“The restoration of The Langley has been an incredible process involving large teams of experts painstakingly regenerating this magnificent historic building to its former glory," said City & Country company director Khalid Affara.

“The sheer size and specification of The Langley Spa help to make the estate an outstanding destination. The whole estate is steeped in such rich history and heritage, we're excited to soon launch a product that successfully celebrates The Langley’s past, while offering contemporary luxury and design alongside outstanding dining.”

When open, The Langley will join Marriott International’s Luxury Collection as part of plans to establish the property on the UK’s high-end hotel market.

Jenni Benzaquen, vice president, Luxury Brands, Europe for Marriott International, added: “Following the meticulous restoration of the estate, The Langley is set to be a stunning addition to the Luxury Collection portfolio."