Leamington Spa Ring Mystery Solved

I just You Tubed 'huge smoke ring' and came across this video, it's almost exactly the same as the ring featured in the video here today, and it's an amazingly simple explanation as to how it was formed. Skip to 1:40. The UK vid from earlier today: http://www.liveleak.com/view?i=279_1397487308 Note how in the featured video we don't get to see how it formed or how it dissipated. ... and another one here which we don't get to see fully develop;