Inflation expectations in five to 10 years' time marginally rose to 3.3% from 3.2% in July, the survey by U.S. bank Citi and polling firm YouGov showed.
Public expectations for inflation in 12 months' time increased to 4.4% from 4.3%.
The BoE is widely expected to raise interest rates for the 15th time in a row on Sept. 21 as it grapples with the highest rate of inflation among the world's big rich economies.
Citi said it expects these data to continue to ease in the months ahead as headline inflation falls back.
"However, these data re-affirm that upside risks around energy in particular over the coming winter could continue to pose challenges."
(Reporting by Juby Babu and William Schomberg; Editing by Daniel Wallis)