Dukes London closed its doors March 20 and will remain closed for at least a month, at which time the company will review its position.
All prepaid reservations will be converted into credit toward future bookings.
Bookings made through May 31 for stays between June 1 and Aug. 31 will receive a 20% discount on the Best Flexible Rate.
The historical Mayfair hotel, a five-minute walk from Buckingham Palace, features 87 rooms, including 15 suites; the Great British Restaurant; Dukes' Bar; the Drawing Room and Conservatory; and the Cognac and Cigar Garden.
A private members' Health Club features an exercise room, steam room and treatment rooms.