Today is dubbed ‘Fat Cat Thursday’ as top bosses will have already earned the average UK gross annual salary of £28,758 for working just three days.

The calculations from think tanks The High Pay Centre and Chartered Institute of Personnel and Development (CIPD) reveal that the ratio of CEO pay to the pay of the average full-time workers stands at 120:1.

However, the analysis showed that FTSE 100 CEO pay did fall last year as the new era of transparency on pay came into effect.

Last year, the mean FTSE 100 CEO pay packet fell by a fifth, down from £5.4m to £4.5m, but the gap in pay between the top and typical workers remains wide.

Peter Cheese, chief executive of the CIPD, said: “The drop in pay in the last year is welcome, although relatively marginal, and will have largely been driven by the growing public and shareholder concerns and the Prime Minister’s stronger focus on boardroom excess and plans to reform corporate governance.

“To ensure this year’s fall in CEO remuneration isn’t just a blip on the consistently upward trend of recent years, it’s crucial the government keeps high pay and corporate governance reform high on its agenda.

“We need a significant re-think on how and why we reward CEOs, taking into account a much more balanced scorecard of success beyond financial outcomes, looking more widely at the impacts of businesses on all stakeholders from employees to society more broadly.”

The TUC, which represents 5.5 million workers in the UK, said the research shows the government must do more to make the economy fair again.

General secretary, Frances O’Grady, said: “Workers are suffering the longest pay squeeze since Napoleonic times. But fat cat bosses are still getting salaries that look like telephone numbers. The government needs a plan to make the economy fair again.

“Workers should be given seats on pay committees to bring some common sense and fairness to boardroom pay. And the minimum wage should be put up to £10 an hour as quickly as possible.”