Be quick: United is offering one-way tickets from the US to London for just 23,000 miles.

If you want to take advantage of this United Airlines promotion, you must move quickly.
Very quickly, as in You must act right away to take advantage.

Today only, United MileagePlus members can book one-way economy flights from a variety of U.S. locations (including 23 nonstop options) to London's Heathrow Airport (LHR) for just 23,000 miles (plus taxes and fees).

If "23" is your new lucky number, make a reservation as soon as possible on United's website.

Boston Logan International Airport (BOS), Chicago O'Hare International Airport (ORD), Houston George Bush Intercontinental Airport (IAH), Los Angeles International Airport (LAX), Newark Liberty International Airport (EWR), San Francisco International Airport (SFO), and Washington, D.C.'s Dulles International Airport are just a few of the U.S. locations from which you could fly nonstop (IAD).

With this offer, you can go via any mainland U.S. airport, not only those on United's nonstop routes, if you don't care whether you take a direct flight.

The offer was visible for trips with one stoppage to and from Miami International Airport (MIA), Portland International Airport (PDX), and Seattle-Tacoma International Airport (SEA). 

You could also choose LHR as your starting point.

As always, there are a few restrictions and limitations.
Taxes and fees start at $191.75 one-way, and your trip must be completed by May 18 of this year.
Only new award reservations are eligible for the deal.

Unfortunately, there are no blackout dates that apply to this specific offer.
You can reserve an unlimited number of award tickets.
Although you are not required to purchase a round-trip option, you are free to do so if you'd rather book a one-way ticket.

Browse the complete terms and conditions for yourself before pulling out your credit card.

Verify that you are utilizing your miles as efficiently as possible.
According to our most recent estimates, United MileagePlus miles are worth 1.21 cents each, making a spend of 23,000 miles worth $279.

Other transfer partners for the reward program include (but are not limited to) Marriott and Hilton.