Sceptics will think it the work of humans with a fondness for figures and a
penchant for puzzles.

But whatever its origins, the experts say it is the most complex crop circle
ever seen in Britain.

The pattern appeared earlier this month near Barbury Castle, an Iron Age hill
fort above the village of Wroughton in Wiltshire.

Initially, crop circle enthusiasts were stumped as to its meaning and even a
number of experts said it was 'mind-boggling'.

Then retired astrophysicist Mike Reed saw a photograph of it and made the
mathematical link.

He said the crop pattern 'clearly shows' the first ten digits of pi, which -
as many will remember from their schooldays - is used to calculate the area
of a circle using the formula Pi r squared.

Mr Reed said: 'I noticed a photo of the Barbury Castle pattern. It shows a coded
image representing the first ten digits of Pi - the ratio of the circumference of a
circle to the diameter.

'The tenth digit has even been correctly rounded up.

'The little dot near the centre is the decimal point. The code is based on ten
angular segments, with the radial jumps being the indicator of each segment.'

After working out the sequence, Mr Reed produced the accompanying diagram.
The image is an example of what is known as a fractal, or geometric pattern.

Fractals have been a staple of crop circle designs for many years, the most well
known being the Mandelbrot Set or the Julia Set, which appeared 12 years ago in
Avebury Trusloe, Wiltshire.

Lucy Pringle, a renowned researcher of crop formations, has the largest database
in the world on the phenomenon.

She said yesterday: 'This is an astounding development - it is a seminal event.'

Although numerous-individuals have come forward over the years admitting they
had been making crop circles, many people still believe the rings are linked with
the paranormal or civilizations in far-flung galaxies.

As yet, no one has claimed responsibility for the Barbury Castle circle.