Why does the British Government consistently turn a blind eye to this corruption by "foreign officials" (AKA Crooks)?
They don't... they've introduced new legislation and the NCA is trying to crack down on the issue. You might well find that these cases are rather complex and take time.
I gather that there are any number of tower blocks in London where there are no lights on in any of the windows at night for 11 months of the year and the underground car parks are full of cars covered in dust sheets.
That doesn't imply money laundering per say... for every property held by some Russian/central asian gangster/corrupt politician there might well be dozens owned by say overseas investors just looking for a safe haven for their assets etc...
Perhaps we ought to ramp up taxes on vacant/unused properties, especially those in prime central London areas where others would benefit from using them but that is another matter...