Seeing some very low ex-LHR business class fares over the holidays. LHR-JFK is in the $1500-range, all-in, round-trip. Other destinations don't seem to be much more - booked LHR-MSP/JFK-LHR and LHR-MSP/PBI-LHR for around $1600. These are non-refundable/non-changeable fares. Lots of other carriers seem to have matched, if you wanted to spread the love.