My steel tourer will last longer than me. Whilst it cost a lot more than the cardboard bike, initially, it works out cheaper over a lifetime of a person I would think. So the answer is not to buy cardboard rubbish that's only got a six month lifespan, but buy a decent bike in the first place.

helen simmons, Norfolk, UK

Any brakes?

I love that cup in the middle of the frame.

Patrick Simpson, Oxford, UK

Hey everybody: this was a design challenge.
Another way to say it is: here's a possibility. Nobody else has thought of this. What have you come up that may possibly solve a problem?
Let's come up with 7000 workable/build-able ideas, some of them are likely to work: that's the whole point.

Lloyd, Austin,

What a brilliant design! Light and cheap. Less energy needed to get up hills. Well done Phil.

Sally, Leeds,

Well, since 12 stone = 168 pound, supermodels have joined the ultrafat kids.

Ed Monbwef, palo alto, USA

Metal is not a problem to recycle, plastic is the enemy! But since it comes from oil it will continue to pile up in landfills and oceans.

nemo, Hamilton, USA

'' the bike was strong enough for a rider weighing up to 12 stones '' So the bike is only built for children and super models?

Oggie, Leigh, England

The tires, chain, and sprocket will cost more than £15. Also, if you are having your bicycle photographed for publication, you ought to make sure the chain is tensioned properly.

john, philadelphia,

You don't have to cut down trees to make cardboard. You can make it from recycled paper and even from old rags.

Anyway, metal isn't that harmful to the environment, it can be recycled too, and it lasts much longer, so why bother?

M. R., Stockport,

But how comfortable, or fast or tiring is it? Since it cost £15 to manufacture I guess it will sell for about 70 but for most people spending somewhat more for a comfortable bike that will last years will make more sense.

neil craig, glasgow, scotland

What are the tires, gears, hubs, chain, and seat made of?

Doug, Orlando, USA

Clellie G - "cool" , and like it says in the first paragraph , the kids can leave it in the rain. As far as Chris and Marco - the bike seems to be made of recycled cardboard , ergo no trees to be cut .If a jet crashed exactly on the boarder of Canada and the US, where would they bury the survivors?

Josh, London, uk

That is so cool, but I think it would be horrible for kids, because you can't leave it in the rain by accident, because it can melt, right?

Clellie G., Hockessin, Delaware US

"how many trees would have to be cut down to produce the 100 of these the average person would need to see them through a lifetime's cycling" Average person? maxiumum capacity of 12 stone?; does this make me above average?

Chris, York,

how many trees would have to be cut down to produce the 100 of these the average person would need to see them through a lifetime's cycling - in any case, would it not be better to spend the 1500GBP on three decent bicycles over 50 years rather than on 100 of the cardboard ones?

Marco, Krakow, Poland

or do as many of us do here- import bicycles from Western Europe en masse and 'recycle' them by using them again -?

Marco, Krakow, Poland

Life expectancy of six months means three or four months in Intensive Care before biting the dust.

M Khan, Peterborough, UK

Would have thought all cycles were recyclable,.....

SID WILSON, NEWCASTLE, United Kingdom

“The lightweight quality of the cardboard, combined with its low cost, means it’s possible to create a bargain bike that’s also less susceptible to thieves.”

but not to arsonists?

james , winch, hants

But all steel and aluminium bikes are already recyclable: in fact the metal in them is likely to have already been recycled many times. So this is a solution to a problem that doesn't exist.

I agree that it is unlikely to be stolen, however.

Stephen, London,