The Grove, part of the ancestral home of the Earls of Clarendon, set in 300 acres of Hertfordshire parkland at Chandlers Cross, is to become Sequoia at The Grove – a spa and health club opening this September.

Created around the original listed stable buildings, restored by designers, Collett Zarzycki, the 2,500sq m spa has been developed with ESPA International (UK). It will be one of only 10 worldwide sites to offer the ESPA Ayurvedic treatments, which encompass aromatherapy, hydrotherapy, thalassotherapy and phytotherapy.

Susan Harmsworth, founder and creator of ESPA said: "To ensure that the Sequoia philosophy and concept are translated into the ultimate five star client experience, ESPA has created a new and uniquely individual menu of treatments, which will be launched to the UK with the opening of this quite exceptional spa."

The interior of The Grove has been designed by Fox Linton and houses 227 rooms and suites – many with balconies or terraces; some with working fireplace (even in the bathroom). All have views over the gardens and parkland, through which runs the river Gade and the Grand Union Canal. The "romantic but formal" gardens by Chelsea Gold Medallist and judge, Michael Balston, are intended to "echo" the mansion’s architecture and provide a series of peaceful, scented spaces and private terraces for relaxation.

Managing director Michel O’Dwyer, says The Grove is family-owned, with no corporate head office: "We have a can-do, modern attitude. In the country, but close to London and Heathrow. Exclusive, yes. But not excluding.

"We believe we are one of the most significant hotel developments in this country for many years, given the range of the facilities, the size of the grounds and the fact that we are within the M25."

Twelve multi-purpose treatment rooms with en-suite showers will be used with heated beds and individual controls for lighting, music and air-conditioning. A "self-sufficient" VIP couples suite will also be available with a double-sized private steam/shower, treatment tables, a self-contained vanity area and changing facilities, a relaxation area and an ergonomically designed, mosaic-tiled bath for two.

Newly created body wraps have been designed, including the Body Toner, the Immune Booster, or the Stress Reliever with Oshadi clay, marine mud or algae and essential oils.

The 250sq m fitness studio will house a Technogym Excite range of equipment from Italy; the 102sq m exercise studio with offer a range of classes from Pilates and Yoga to circuit training and aerobics.

A 22m indoor swimming pool is to be set in a colonnaded oak barn. The black mosaic tiled pool is to be illuminated from within so that light catches whoever is in the pool.

Pedicure "thrones" from Taiwan will feature in the manicure/pedicure/make-up salon with vibrating, reclining chairs. Bespoke make-up stations will be used by therapists using the Vincent Longo range of products.

Separate male and female heat experience areas will each have a crystal steam room, a Finnish sauna and a Turkish hammam. The vitality pool has 11 individually controlled stations to massage the body with jets of saline water.

Relaxation rooms will be furnished with beds by Royal Auping with integral reading lights and music.

The spa is planning to be "parent-friendly", offering a children’s centre (opening in 2004) with indoor swimming pool, indoor and outdoor play areas and an entertainment programme. An 18-hole championship golf course is also provided, designed by Kyle Phillips, whose work includes Kingsbarns Links in St Andrews, Scotland.

Open to hotel guests, members and outside guests on spa programmes, membership at Sequoia at The Grove starts at £2350 plus a £500 joining fee. Day spa programmes are from £200. The Grove is a member of The Leading Hotels of the World. Details: www.thegrove.co.uk