FX.co ★ UK RPI Slips Into Deflation in January, Posting First Monthly Decline Since Late 2025

The United Kingdom’s Retail Price Index (RPI) turned negative in January 2026, underscoring a sharp shift in monthly price dynamics at the start of the year. Month-over-month, RPI fell by 0.5% in January, compared with a 0.7% increase recorded in December 2025, according to data updated on 18 February 2026.

The move from a positive 0.7% pace in December to a -0.5% reading in January marks a notable reversal in headline retail price pressure on a month-over-month basis. The comparison reflects how prices in January 2026 evolved relative to December 2025, while the December figure measured the change versus November 2025.

This negative monthly print suggests that, at least for January, consumer-facing price growth not only slowed but went into decline, potentially easing immediate pressure on household budgets and feeding into broader discussions about the trajectory of UK inflation indicators as the year begins.