The revenue per available room (revpar) figure of £127.24 achieved in London hotels during May is the highest on record for the month, according to preliminary figures published by data company STR.
Hotel performance across the capital also showed a 1.7% year-on-year rise in occupancy to 83.1% and an increase of 7% in average daily rate to £153.04.
London hotels appear to have been unaffected by the terror attacks in Westminster and Manchester, but is too early to gauge any impact following last weekend's tragic events at London Bridge and Borough Market.
Data supplied by STR showed that there was an immediate downturn in business in Manchester following the suicide bombing at the Ariana Grande concert on 22 May. Two days after the attack, the year-on-year occupancy rate in the city fell by 8.5% to 89% and the average room rate was down 13.3% to £85.73.
STR analysts said that May's record-breaking hotel performance in London was driven by the devaluation in the pound and the subsequent boost in leisure business.
Occupancy levels broke the 90% barrier on nine days during May, including during a number of major exhibitions such as the Security and Counter Terror Expo (3-4 May), Museums Heritage Show (17-18 May) and London Wine Fair (22-24 May).
STR will release actual May 2017 results later this month.