Deepest winter wouldn’t usually be the best time to work in the garden. But with the advent of the third lockdown and an order to stay at home for months, any extra space can be welcome.

With working from home – and homeschooling – the new way of life, garden rooms have gone beyond a fanciful indulgence to a must-have. They have raced up the priority list for property buyers too, potentially adding a significant premium to house prices.

During the first lockdown, siblings Rebecca and Tim Saxon used the opportunity to build a garden room at the back of their three-bedroom property in Brixton, south London.

This is far from simply a glorified shed. The L-shaped, 118 sq ft timber structure, edged with slate and York stone patios, features a large picture window that frames views of a mimosa tree that is about to burst into bloom.

Inside the cabin, clad in knotted British western red cedar, there is a built-in desk big enough for two and a separate lounge area.

The Saxons are among a growing number of homeowners who have installed garden rooms and offices to maximise space.

Architects of bespoke garden rooms and providers of off-the-shelf kit and modular cabins reported booming sales last year and estate agents found home offices top of the list for many buyers. Edward Church of estate agency Strutt & Parker said: “They are mentioned in almost every conversation I have.

“While many people have not been missing their usual commute to work itself, people still like the idea of ‘going to work’, even if that’s just a stroll across the garden – they want a mental distancing between home and work life.”

Sellers, too, are cashing in on the remote working trend. Robin Chatwin, who works for the estate agency Savills in south-west London, said a high-quality garden room could add between 5pc and 15pc to a home’s value.

Considering that adding even a small extension usually costs from about £25,000 and brings with it months of mess and noise, plumping for a garden room – with simpler, ready-made models starting from just a few thousand pounds – seems a great way to add space and value. But before you join the pod squad, there are a few key things to consider.

There is a grey area when it comes to planning permission. Garden rooms usually fall within permitted development rights, so don’t require planning permission, as long as they are used for purposes “incidental to the house”. This means that using the space to work from home is allowed, as is using it as a snug or games room, but running an extensive office in such a building may cross the line.

To fall under PDR, garden rooms must also be a single storey and less than 8ft 2in in height. There are rules about how much of the garden it can take up too, so do your research.

If you live in a conservation area or Area of Outstanding Natural Beauty, or want to build on the curtilage of a listed property, check the rules carefully, as you may have to get planning permission.

For the Saxons, their work during the first lockdown has prepared them well for the third one.

“Tim and I bought the house two years ago, for about £695,000, and have renovated it ourselves to save money,” said Ms Saxon, 29, a chartered surveyor. She lives with Mr Saxon, 27, a solicitor, and his girlfriend, Isy Reid, 29, who is halfway through her architectural training at Emrys, as well as two more housemates.

“We had looked at various ready-made garden rooms and pods, but didn’t think we could afford one,” said Ms Saxon.

“Then, when Tim and I were both furloughed in April – and with Isy’s free design skills on hand – it was obvious. She came up with the look and we all built it, with plenty of practical help from YouTube DIY videos.” They spent about £9,200 building the space.

Those not lucky enough to have an in-house architect can buy ready-made garden offices to suit most budgets. You can go for a basic flat-pack uninsulated summerhouse style from about £2,000, but working in a chilly, draughty box may make you reconsider. Companies such as Crane Garden Rooms sell fully insulated and double-glazed rooms from £9,835.

Launched in response to the pandemic, design firm FD Architecture created Modulr Space, garden rooms that come in kits. Its workspaces, with built-in flip-up desks, require no major groundworks and can often be constructed on site in a day. The modular sections can reach the most hemmed-in urban garden and can be dismantled when you move house. They start from about £17,500.

For many, the need for a garden office is proving the perfect opportunity to add some interesting design, with some on the hunt for David Cameron-style shepherds’ huts, log cabins, gleaming globes and space-age capsules.

North Yorkshire-based Anthropods has designed a series of huts that have a naturally futuristic look. Built of sustainable timber and using recycled plastic bottles for insulation, they can be delivered and installed using a forklift or a crane.

In the world of garden rooms, the bespoke, architect-designed model is king. Matthew Wood, founder of MW Architects in south-east London, has reported a spike in inquiries for his Zen-inspired garden rooms since the first lockdown. Those who want one to their own design should expect to pay from £2,000 per sq m for an architect-designed garden room, which covers materials and building work but not architects’ fees and the 20pc VAT on top.

No matter how Instagram-worthy it is, any garden office is only as useful as its Wi-Fi. Malcolm Stewart of Knightsbridge Audio Visual spent much of last year at his clients’ country homes, hastily running cabling from the main house to garden rooms – and then finding that robot lawnmowers and gardeners had cut through them.

His key piece of advice is never to try to make do with a weak, unreliable Wi-Fi signal from the house but to aim for a stable, hard-wired connection provided by running “Cat 6” cabling from the main house to a wireless access point. “An intelligent network, where priority is given to Zoom and Microsoft Teams, for example, will ensure the kids’ sessions on Fortnite and Minecraft won’t interrupt you,” he said.

If you are going to claim the new room as your exclusive escape, though, play fair: don’t build it in the only sun trap in the garden. And being thoughtful enough to install a desk for two might make working from home that bit more harmonious.

Do you have a home office worth boasting about? Let us know in the comments section below.