Two For The Price Of One doesn’t only attract families doing a supermarket shop. The prospect has growing appeal for househunters, too.

‘Annexe’ has appeared more than 100,000 times on the list of features buyers hope to find in their next property since Rightmove added a keyword search field to its website a year ago,

The online agency’s property expert Miles Shipside says demand for a little place on the side far outstrips supply. The need for an independent suite of rooms apart from the owners’ main house stems from adult family members at each end of the age range.

The agent points out: “Lots of young people are priced out of the market at the moment so those who’ve graduated from university for example are living with their parents for longer. They want a place of their own, their own front door, somewhere where their post can be delivered.

“Many people also find it far more suitable to look after a family member than to pay for them to stay in a care home which is often very expensive. An annexe is a kind of in-between space.

“Annexes come in all shapes and sizes. Some are detached cottages, some are semi-detached, some are ground floor apartments. Some are just separate, lockable rooms. They appeal to investors because it gives them two rentable properties.” He added: “There could also be some stamp duty relief when buying a property with a qualifying annexe.”

Pictured is a Grade II listed five bedroom farmhouse in Great Missenden with a guest cottage attached. The house is new on the market at the Beaconsfield office at Knight Frank for £1.8m.

Michael Graham in Princes Risborough is selling a smart four bedroom house in two and a quarter acres at Great Kimble. The views over countryside are glorious. The house was originally built about 50 years ago. The living area of almost 4,000 square feet includes a ground floor fitness suite. There’s obvious potential to turn the gym/media room, sauna, shower and cloakroom into a self contained suite for elderly relatives or boomerang kids. Price: £1.1m.

Savills in Beaconsfield has a five bedroom Victorian country house at Hedgerley with a 4,000 sq ft living area and planning consent for an annexe to add a further 1,000 sq ft. Guide price for this property: £1.75m.

If you consider the cost of the alternatives, joining forces can benefit both sides in a housing arrangement if it protects your independence.