Unknown Insect

Spotted this in the garden. I could've done with some sort of support for my camera as this is hand held.

I tried identifying this insect but the closest I could find, in my reference book, was an insect that had only been spotted in this country on one previous occasion so I guess it's not that. On reflection I'm assuming it is probably a type of shield bug but it looks a bit thinner and longer than normal. Can anyone confirm this?

Album of the Day - Harvest - Neil Young (1972)