Large colourful fly.
No interactions present.
See http://thetopshamnaturalist.blogspot.com/2010/05/scorpion-flies.html. This is a female, and can't be done anyway.
recording wildlife with The Recorder's Year on www.hbrg.org.uk/TRY.html.
Martin Harvey summarised these on iSpot, where pics of the three species can be seen, now.
My Flickr photos...
Excellent links; thanks, ophrys and Syrphus. I'll watch out for males in the coming year.
Lat/Lng: 51.3599, 0.0114
OS grid ref: TQ401642
In the hedge at the edge of the wood.