London house prices have recorded their first annual fall for eight years, the Nationwide says, dropping 0.6% year-on-year in September.
Across the UK, annual price growth slowed to 2%, down from 2.1% in August.
The Nationwide said that London was the weakest performing region in the UK for the first time since 2005.
Robert Gardner, Nationwide’s chief economist, said activity across the UK market as a whole was “subdued by historic standards”.
He said that while low mortgage rates and healthy rates of employment were helping support demand, pressure on household incomes was weighing on confidence.