Ordnance Survey Maps have been integrated within the Google Map Compass tool. Ordnance Survey Compass overlays an interactive compass on an Ordnance Survey Map that matches the UK Google Map location. Ordnance Survey Map routes can then be plotted, with compass bearings, grid references, latitude and longitude coordinates, distances and magnetic variation or declination recorded.
The Ordnance Survey Compass integrated link can be found in the map style menu:

The Ordnance Survey Compass integrated link
If the Google Map location lies outside the UK, the Ordnance Survey Compass will load its default location centred on Lyndhurst, Hampshire.