What is it?

When I saw this field of purple flowers down on the Carse  ( Stirling castle visible on the horizon) today I couldn’t resist stopping and photographing it.
 
But what is it? At first I thought it was a field of lavender, yet we don’t grow lavender in Scotland.
 
Later I consulted a botanist friend. She pronounced it to phacelia, a plant grown as a crop for green manure and as a natural remedy for a variety of conditions including drug addiction, headaches and cold sores.
 
And bees love it.

Link
http://www.dianamossop.com/tabid/223/ref/27/essence-of-phacelia.aspx