A royalty-hosting mansion with an illustrious military history dating back centuries is up for sale for £2.25 million.

Upnor Castle House, which dates from the 1600s and stands in the shadow of the Elizabethan artillery fort, has never before been on the market.

It was built by the Admiralty as a cottage for the senior officer in charge of the castle, which was tasked with protecting warships at nearby Chatham Dockyard. It was expanded to become a fine example of a Georgian country home.

In later years it became married living quarters for high-ranking army and Royal Navy personnel.

That was until the 1980s when the Ministry of Defence started to sell off huge chunks of its property portfolio.

In 1985 it was acquired by naval commander Felix Barber who left the deeds to his daughter Nicky and son Justin when he died in 2001.

Nicky and husband Mark Harris – a former Army major – have lived there since with their daughter Charlotte, 26, and son Alex, 22.

Crisis management consultant Mark says it was with "mixed emotions" that now their children had grown up, they had decided to sell.

The 61-year-old said: "It's a wonderful family home and it's now time another family enjoyed it.

"It's in a fantastic location with a wonderful garden, ideal for children to play in and make dens.

"It's a house that responds well to gatherings without tripping over yourself and at the same time have lots of fun.

"Not everyone can say they have a castle at the bottom of their garden."

The family home is particularly close to his heart because his father, who was in the Royal Engineers, moved in when Mark was aged about six.

The former officer and physiotherapist Nicky have got used to village life and socialise in the local pubs.

He added: "We don't plan to move too far away, so will be coming back for visits."

The earliest building at Upnor Castle House was thought to have been a small two-storey dwelling.

But the improvements in the mid-17th century probably included the first phase of the present house.

Although the exact date is not known, a small silk and leather shoe found during the course of restoration work, has been dated between 1660 and 1680.

Hiding a shoe in a wall or loft space was a custom which was thought to keep away evil spirits and bring good luck.

It also boasts a mulberry tree in the walled garden reportedly planted by Elizabeth I on a visit.

In 1807, the Admiralty decided to upgrade England’s defences and it is believed at this point Upnor Castle House was enlarged and re-fronted.

The likely designer was Edward Holl, architect to the navy board.

This gave Upnor Castle House the very elegant Georgian façade overlooking the gardens which run down to the castle grounds.

The spacious reception rooms and principle bedrooms on the first floor signify this was a house of some importance.

Set in four acres, it boasts tennis courts, a swimming pool, croquet lawn, nine bedrooms, a holiday cottage and separate outbuilding which could be converted into a gym or office.

David Lane, of Medway estate agents Machin and Lane, said since going on the books in mid-July, two offers near the guide price has been received and were currently being considered.

There had been a lot of interest from near and further afield, in particular the London area, and they had overseen about 20 viewings.

Mr Lane said in terms of status and history, it was one of the biggest properties he has handled in his long career.

There is potential to build a separate property on the northern corner of the land, subject to planning consent.