The inventor who specialises in making miniature objects has a new big idea. A collapsible bike designed to fit a commuter journey as easily as it folds to squeeze into a bag.
He brought us the pocket calculator and the ZX Spectrum, the digital wristwatch and the ill-fated C5 road buggy. Now Sir Clive Sinclair has turned his attentions to the humble bicycle.
But put it to the test, is it just a bit, well, wobbly?
After the 7 July Tube bombings, congestion charges in UK cities, and with normal-size bikes forbidden from commuter trains, fold-up bikes are increasingly taking to urban streets. And it is a busy market. UK leader Brompton shifts 15,000 a year, around the globe, of its proper bikes designed to fold.
But designer Alex Kalogroulis and Sir Clive say the A-bike is different, and smaller still. That it stands out from the competitors as an "ultra-compact" bike for "short hop" journeys - two miles from home to the Tube or from the train to the office. Pedals and handlebars mean it is a bike; tiny wheels means it doesn't do distance.
Named after the shape of its telescopic black-and-silver frame, it claims to come in at half the weight, (12.5lbs) and half the price (£199) of those already on the market. It has two chains, one gear and a weight limit for riders of 13st 5lbs (85kgs).
Sir Clive says: "I thought, if a bike could fold compactly and be lighter than bikes today, it could fulfil a lot of needs. A 15kg bike is fine if it's carrying you, but if you are the one that carries the bike, that changes it."
The bike was unveiled on London's South Bank, with the hoped-for customers in the City in view across the river.
But the sight of its tiny wheels - the size of a late-90s micro-scooter - and its novel design raised the question, "Is this a bicycle, or a £200 toy starting an early run up to the Christmas market?" The only way to answer that is to put the A-bike to the test in the hands of the experts - the cyclists.
Down with the kids
Cycling in the UK's towns and cities brings two main dangers. One is getting a bit sweaty. The other is more serious: death.
Dicing with traffic and pot holes on busy roads is a daily hazard. Being able to avoid them is essential. Could the A-bike with its tiny profile hold its own on the mean streets of urban cycling?
Truths often come from the mouths of babes and in this case from a Year 7 class of 11 to 13-year-olds on an art trip to draw Tower Bridge.
They tussled to ride the bike. Declared it "lightweight and cool", "better than my BMX" and made plans to scale down the A-bike to sell it for children look like a canny marketing strategy.
But they also spotted what each of the test-riders found: "The handling is a bit hard to control," shouts Alex Roberts, 12, over his shoulder, as he veers wildly across the south embankment.
What about in the hands of a seasoned professional? Lance - not Armstrong, but Foster - at On Your Bike cycle shop takes the A-bike for a carefully-executed spin down the pavement.
His "How does it collapse then?" demand is the signal for three minutes of faffing from journalist, photographer and bike-hand. As with all "folders", as they are known in the trade, familiarity will hopefully breed speed.
His verdict on the bike is fast, strong and insightful. There is much that he would change: "First of all that seat is definitely the most uncomfortable seat I have ever sat on.
"Plus, the way those handle-bars fold in - I would have made them a bit longer. With the geometry of the bike you need them for good, aggressive speed.
"And, when you turn, it is very unstable."
As for the regular cyclists, student Felix Tanzer, 21, finds there is more than a weight restriction for riders. "I think it's designed for the small-of-leg," he laughs, as his knees knock the handle-bars.
Again, the "fairground wobble-bike" style of riding is on display. "But once you get on, it's not so bad," he adds. "Just a little bit wobbly. If I wasn't wearing ridiculously-big sandals, I would find it easier."
Folds 'in 10 seconds'
Riders below 13st 5lbs
One design in red, black and silver
Two chains, one gear
Would he stretch his student budget to buy one? "No." He is too near the Tube to need one in London. He fears the bike would be laughed at back at university in Bristol. And he doubts it could cope with the hills, the wind on the Downs, the blasts of winter weather.
If the bike is meant to fit in to a commute, how does it fare on the Tube itself? It packs neatly into a shoulder bag or can be carried by the handle bars. It is out of the way on the escalator step or the carriage floor, much like any folding bike.
Achy-arm sets in on the streets, but there is a bag to ease the load
But achy-arm from carrying it is quick to surface, and how everything else would be balanced is less clear. Especially with the amount of gear cyclists tend to trail.
The A-bike's distributors hope to shift 15 to 25,000 in the first year. That is quite a projection in the current market. Kids may want one, but everyday commuters could well demand more of a bike for their buck.
Whether it becomes a success, or a "collector's item" along the lines of the C5 in the 1980s, looks likely to depend on how many A-bikes Santa can fold down and pack into his sleigh.