Can you buy puncture proof 700x40C bicycle tyres?

Short answer, yes. Long answer, they sell tubes with a gel inside that seals small holes. They also sell liners that go between the tube and tire.
There is a company that is developing solid tires that actually work, but I'm not sure they are on the market yet. Try googling it.

Papa Wheelie
January 2011

you can buy tube protecters they fit between tube and tyre or you can get steel belted tyres

mad 1014
December 2010

Well now this is an eye opener for me you can apparently for mountain bikes.
There are two currently on Ebay latest bid £10.50 type in search 2 new solid bike tyres it may come up. And to admit I thought you were 'aving a laugh ' I owe you an appology, it seems for certain bikes we have moved on but doubt the same for road bikes but if the size is right why not!

Bob
September 2010