The median pay for chief executives of FTSE 100 companies fell by nearly a fifth over the past year, according to accountancy firm Deloitte.

The UK's top bosses took home £3.5m ($4.5m) this year compared to £4.3m in 2016 – a 19% decline.

Deloitte said in its remuneration report that government policies introduced to limit bosses' pay appeared to be working, the BBC reported.

The government introduced new rules in 2013 to give shareholders a binding vote on directors' pay amid investor anger over rising executive salaries at a time of falling share prices.

Companies have to subject their pay policy to a binding vote every three years and publish yearly data showing how much executives are being paid.

Prior to the rule change, shareholders voted annually on executive pay policy but the vote was non-binding, meaning the board could ignore the result of the vote.

"The fall in executive pay demonstrates that remuneration committees are making a real effort to address shareholder concerns," Stephen Cahill, vice chairman at Deloitte, was reported as saying.

"This is the first cycle where the legislation introduced in 2013 and primarily voted on during the 2014 AGMs (annual general meetings) will have taken effect.

"It seems the current legislation is working."

Prime Minister Theresa May unveiled additional proposals to curb excessive executive pay last year, but she has abandoned some of the more radical reforms over concerns that her minority government will not be able to get them through Parliament.

The prime minister backtracked on plans to put workers on company boards last year amid opposition from business leaders.

A separate survey on executive pay released by the High Pay Centre earlier this month revealed that average earnings of FTSE 100 bosses fell 17% last year to £4.5m.

The study found the pay ratio between chief executives and their employees was 129:1 last year – meaning for every £1 paid to the worker, the CEO received £129. In 2015, the ratio was 148:1.

WPP's Sir Martin Sorrell was by far the highest earning boss in the UK last year, taking home £48.1m.