It's a mixture of satellite imagery and aerial photography - what's used depends on the location and the 'virtual altitude' / height (i.e. as displayed in Google Maps / Earth), and I think what you can get at some altitudes is a certain meshing of the satellite and aerial imagery together.

The imagery in the OP's link certainly looks like high quality aerial imagery to me, much like the rest of the coverage of London and indeed other (western) cities at that 'virtual altitude'.