By Ben Jeffrey
BBC News, West Midlands
A pair of entrepreneurs are planning a 2,000-mile road trip without ever getting out of their car - not for food, fuel, or even to relieve themselves.
The Indipod's fan is designed to drown out embarrassing noises
If Barbara May and Dr James Shippen complete their week-long journey from John O'Groats to southern Italy, they are sure that it will be a unique feat.
After all, unless you have a bladder the size of Luxembourg, or a willingness to endure the most unimaginable kind of squalor, how could such a trip be possible?
Only by having a toilet in the boot of your automobile, like this pair of Bromsgrove-based inventors.
With the help of their inflatable loo - the Indipod - a supply of food and drink and a team of helpful petrol station staff in four different countries, they are hoping to win an entry in the Guinness Book of Records.
As Ms May explained to BBC News, the innovative element to their product is not the toilet itself, which is a standard chemical contraption, but the inflatable hood which surrounds it.
Ms May, managing director of Daycar, the company behind the invention, said: "The bubble is the new part. It gives you total privacy.
"There's a fan unit which inflates the bubble. It's slightly noisy - when you go to the loo, you don't want people to hear you."
The Indipod is designed for use in large cars or vans
The £295 device has dimensions of 20ins x 19ins x13ins - "the size of a small suitcase" - and is powered from a lead to the car's cigarette lighter.
Ms May said they would be stopping at a variety of locations in Scotland, England, France, Germany and Italy.
"We'll literally just be looking out of the window," she said.
Several petrol stations in the UK have already agreed to help in the challenge, both by filling up their car with petrol and providing the inventors with food and drink.
"When we're in France Germany and Italy it's going to be more interesting, let's put it that way."
She said she and Dr Shippen had reasonable conversational French and a "smattering" of German, but added: "In Italy it's going to be wild gesticulating and a phrase book."
And although the pair's road trip is intended to be a light-hearted affair, they hope the Indipod can improve the lives of people with serious medical conditions such as Crohn's disease, which causes sufferers to make frequent toilet trips.
Ms May said she thought the Indipod, which is designed for use in large estate cars and minivans, could also prove popular with young families and people taking driving holidays.
And the business partners, who also run a biomechanics company, say they are taking the necessary steps to ensure they do not become medical casualties themselves.
"We're aware of the risks of DVT (deep vein thrombosis).
"We've got colleagues who are physiotherapists and they've given us exercises for us to do every two hours."
The inventors are setting off from John O'Groats on Monday 11 April and aim to reach southern Italy by 19 April.