Can someone tell me what this bug is?

[broonstane]

Can anyone identify this bug for me? I found it while walking the dog in a country park in Kilmarnock, Ayrshire, Scotland. This was at the beginning of April 2012. I've lived in this area for over 30 years and have never seen anything like it before. It had such straight lines and was almost triangular in shape, probably around 2-3 cm in length.

Thanks in advance.

[Darby]

Definitely a hemipteran, kind of looks like a leaf-hopper of some sort.

[wbla3335]

My first impression was also a leafhopper. But I'm no entomologist. Leafhoppers come in many colours, shapes, and sizes. Some are green and triangular.

[vk4vfx]

It looks like some species of katidid but I'm no entomologist either.