Audit income for the Big Four accountancy firms rose 6.9% in 2019 as they maintained their iron grip on the FTSE 100 audit market.

Data released by audit watchdog the Financial Reporting Council FRC showed EY, KPMG, Deloitte and PwC audited the entire FTSE 100 last year and also dominated the FTSE 250, with only two firms outside the Big Four auditing at least 10 companies on the index.