You go there to spend a penny, only to find the owner has spent a fair bit more – not to mention a lot of imagination – on making sure the smallest room in the house makes the biggest statement.

Herts Advertiser: The DagobertThe Dagobert (Image: Archant)

No matter how tastefully designed and conservatively themed the rest of the house, the cloakroom (downstairs loo in other words) is often the place owners tend to get the most creative.

Caves, rainforests, Victorian workhouses, you name it, I’ve washed my hands in mini film-sets of rooms under stairs or along corridors of those with the means and the inclination to let their imagination run riot.

And they don’t always have to be expensive. In fact, one TV personality I visited once or twice used hers as a virtual scrapbook, covering the walls with newspaper cuttings of herself.

And I always used to know when one particular literary agent took on a new client by the new books that suddenly appeared on the mini shelving unit in his. All placed at eye-level, of course.

Herts Advertiser: Nautical ReinventedNautical Reinvented (Image: Archant)

Another had created a series of display cabinets to showcase exotic-looking mini-soap bars from what looked like every luxury hotel in the western world – and left a Dove soap dispenser on the, albeit ornate, basin for guests to use.

This sense of adventure is not unusual, according to those in the know. Kiev-born Anna Grace-Davidson, the founder of the prestigious Mayfair brand Anna Casa, said: “Designing cloakrooms is very different from other spaces in the home and it can be a lot of fun.

“Every time I work on a new project and there is a cloakroom included, there is more freedom to express yourself and be more creative and brave in your decorating ideas. Adventurous cloakrooms are a nice touch; hidden away from view and an unexpected surprise from the rest of the home.”

Locally-based designers agree and say it’s not only celebrities who follow this trend.

“It’s because it’s not a living space as such. It’s transient, like a hallway so, naturally people can be that bit more daring,” says Sarah Pritchard of the St Albans-based interiors consultancy, The House Clinic: “It’s seen as a space where you can be more experimental and show off because, of course, guests will actually use it whereas they won’t venture to other areas of the house.

“And, if you’re not all that experienced or particularly good at DIY this can be quite the perfect starting point as it’s such a small space. And it’s flexible. If you paint the place bright pink, for example, and decide it’s all gone a bit pear-shaped, it’s only a matter of a tin of paint to put it right.”

Advances in lighting and sanitary-ware have been a boon for householders seeking ways of creating drama, citing the inclusion of 70cm-high taps in a recent project as an example. Wall finishings these days, she says, are in “a league of their own”.

Deborah Fitz, who runs a design consultancy from her home in the Poets area of Harpenden, agrees.

“I have been in houses that are quite neutral and then opened the door of the cloakroom to find something completely bold and different,” she said. “And it doesn’t really matter if people like it or not. They’re only there for a few minutes, after all.”

And does this creativity crave the attention of a design guru like her? Or are people happy to take on that particular task themselves?

“If I’m doing the whole house, they’ll probably want me to incorporate it into the plan. But if it’s only a couple of rooms, it’s unlikely to include the cloakroom.

“In fact, people may actually be quite embarrassed to say ‘come and design my downstairs loo’, so it tends to be a DIY thing. And that’s OK. It’s a small room where they can be left to their own devices.”

As for trends, many experts say the advent of new purpose-designed timber products will keep wood front of mind as a design feature for some time, as will metallics which can be used to add striking industrial accents, reflect light effectively, and work well with natural materials.

And there are few of the sort of dilemmas that usually trouble designers. Natural light, for example, is not normally a priority in such confined spaces and storage needs tend to be fairly minimal, so the way is generally clear to concentrate on the visually creative.

Wallpapers are big at the moment. From giant fish to cute cartoons you can read and re-read, blackboard-and-chalk designs and quirky images like tiny cisterns such as Toilet Heaven by the online retailer Wallpaper from the 70s. You can get a graffiti artist in to doodle to order or plump for something far more subtle and calming such as a statement boat scene Nautical Reinvented, available from B&Q.

Some designers have done quite innovative things, using everything from hanging plants and vintage road signs to enhance open brick walls to reclaimed ironworks and ladders cut down and bleached for effect to fit as towel rails. High-gloss paint and sparkly tiles are quite popular on floors and taps in matt black or gold – pink, not the usual rose tone – give a nice, clean brassy look and work well with natural woods. Sinks now even come, not simply in a range of shapes and sizes, but materials as diverse as soft, pliable polyurethane.

But if all that sounds too fussy, you could always plump for a good old-fashioned trip to the throne - literally.

The Dagobert, an imposing wood and porcelain structure designed by the fourth generation owner of the Herbeau Company of Lille, France, features a musical lift-up lid and hand-painted ceramic coat of arms featuring a poem.

Tina Turner and Boris Becker are both said to have one. Not that singing seats come as any surprise to the experts.

Anna Grace-Davidson recalls: “We designed a cloakroom for one client with a back wall with red theatre curtains. The idea was that, every time a guest or anyone used the room there would be a round of applause! It was definitely memorable.”