Delta currently has a Delta SkyMiles promotion for round-trip flights from Seattle (SEA) to London (LHR) for 34k-40k points +$205 tax/fees. Flights October through February.
Most nonstop flights are midweek, other days tend to have more connections.
If you have the Delta SkyMiles® Gold American Express Card, you get an additional 15% off this published rate (example: 40,000 would be 34,000 points for London after the discount). Terms apply. American Express is an Escape Flights advertiser.