The Trades Union Congress' (TUC) new CEO pay report found on average CEO pay rose 39% from 2020, when the gap was 79 times the pay of the average worker.
The highest paid CEO in the report was media company Endeavour's Sébastien De Montessus.
He took home £17 million in 2021 which was 539 times the pay of a median full-time UK worker.
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There is a persistent gender pay gap among CEOs too.
The average pay for female CEOs in FTSE 100 companies was £3.01 million in 2021, 16% lower than the £3.49 million for male CEOs.
Out of the 98 companies covered by the report, just nine had a female CEO, up from seven in 2020.
Anna Whitehouse, author and founder of flexible working campaign Flex Appeal, highlighted the need for more women in senior roles.
Speaking to HR magazine, she said: “That just nine female CEOs sit on the FTSE 100 companies in the 21st century is utterly disappointing, that the pay gap between male counterparts has increased is devastating.
"Gender pay gap reporting exists to highlight inequalities in the workplace so that we can strive to bridge the gap. But we have to work towards bridging the gaps, otherwise the system will just stay broken.
"If we as a country are serious about levelling up, we need to get more women at the table. Without women leading the charge we are missing a crucial lens in business and valuable experience that cannot be filled by hiring even more CEOs named John."
Whitehouse added that proper flexible working practices will help keep senior women in the workplace.
She added: "We need to make the workplace work for women. Senior women should not fall out of the workplace because of a workplace that doesn't enable them to work to their potential. Flexible working has been cited as the number-one way that we will close the gender pay gap, and yet we still aren't advertising flexible working in more than one in four jobs.
"If we're serious about change, then we need to start from the top, and bring this number up from 9% to 50% and we need to pay these women properly from day one."
