British consumer sentiment has fallen to a six-year low due to increased worries about job security and the impact trade tensions and political uncertainty will have on individuals' finances, a survey showed on Thursday.

Market research company YouGov said its monthly consumer sentiment indicator, compiled with economic consultancy Cebr, dropped to 103.4 in September from 104.0 in August, its lowest level since May 2013.

"It is clear now that the UK has shifted into a slower growth mode due to a combination of ongoing domestic political uncertainty and global economic headwinds," said Kay Neufeld, head of macroeconomics at Cebr.

Figures from pay analysis company XpertHR, also released on Thursday, showed that the average basic pay settlement at large employers remained at a 10-year high of 2.5% in the three months to the end of August, unchanged since the start of the year.