Lenders approved 58,977 mortgages for house purchase last month, down from 65,967 in September. A Reuters poll of economists had pointed to approvals of 60,200.
Britain's housing market is showing clear signs of slowing, with various gauges of house prices now showing cooling inflation after rapid growth during the pandemic.
A Reuters poll of economists and property market analysts last week showed house prices are forecast to drop around 5% next year, having risen about 24% since early 2020, according to official data.
Tuesday's BoE data showed the net increase in mortgage lending in October was smaller than expected at 3.966 billion pounds ($4.75 billion), down sharply from 5.878 billion pounds in September and marking the lowest reading since November 2021.
Consumer borrowing increased in net terms by 769 million pounds in October, picking up slightly from September's 608 million pounds rise.