Business confidence slumped to its lowest level on record last month amid concerns over soaring costs, according to a new survey of company bosses. Data from the Institute of Directors (IoD) showed that firms said higher labour costs has been the biggest contributor to growing pessimism about the economy. The industry group’s monthly economic confidence index, which measures business leader optimism about the prospects of the UK economy, posted a minus 74 reading for September. Around 83% of surveyed leaders linked the worsening outlook to higher labour costs, while supply chain inflation and energy costs were also highlighted as significant factors. Anna Leach, chief economist at the IoD, said: “Business confidence has plumbed new depths in September, following a fleeting improvement at the tag-end of summer.