British households' worries about the outlook for their personal finances rose to their highest in almost six years in September, pushing a broader measure of consumer sentiment to a four-month low, a monthly survey showed.

The IHS Markit Household Finance Index sank to 43.1 in September from August's reading of 43.6, driven by greater reluctance to make big purchases, concerns about job security and the most negative outlook since November 2013.

"The latest data suggest that the robust performance of the UK labour market may not be sufficient enough to dispel the pessimistic financial outlook, which could ultimately see weaker consumption trends at a time where the economy hinges on domestic resilience," IHS Markit economist Joe Hayes said.