Red and Yellow and Pink and Green...

When I'm not hard at work in Mishmash Bookshop, I retire to live in the beautiful south London village of Camberwell.

One of the many truly astonishing things about Camberwell is the quality of it's rainbows.

During this afternoon's heavy showers, followed by sunshine, I knew we would be in for a treat, and I wasn't disappointed. The shot above is from last year, and doesn't do them justice. It was taken looking east, over the village, from Myatts Field Park.

Now, I was educated in Scotland in the 1970's, so I know what a rainbow is. They are caused by sunlight is being marginally refracted through the water vapour in the air. The reason you can see 'twin' rainbows in the best examples is that the refraction is happening in a converging pattern towards you, and the slower red light bends into the centre. So that box is ticked.

But my question is - Why, after a fair amount of rural life, and a lot of mountaineeering both in Scotland and abroad, does Camberwell have the most vibrant rainbows I have ever seen, and the most regular occurance of the twin rainbow?

I have thought long and hard about the effects of poor air quality, the temperature, the southern boundary of the long-gone Thames flood; but I just can't figure it out. So can anyone either explain this phenomena, or at least point me towards any historical resourse that will confirm it?

I will buy the most convincing respondent a pint in Camberwell's fantabulous Sun and Doves.

Andrew Mishmash