There are a number of new listings on Booking.com (May 29) of central London luxury apartments at about 20% of real price. The scammers ask for a significant damage bond (1000 GBP plus) to be sent by bank transfer at booking time. They will send you an email via the Booking.com system asking for your email address which they do not get from Booking.com.
I found one of these apartments listed with Savills at $12,500 GBP per week and the price on Booking.com is about 1600 GBP per week. I then searched central London listings and found about 6 more posted on May 29.
I use Booking.com regularly and it is a great site but someone is going to be screwed over here. Loss of 'bond' and nowhere to stay when they arrive.