Britain's top executives are now paid more than 140 times the wages of their average employee, according to a new study.

Executive pay has increased "dramatically" in relation to most workers over the past 30 years, said the High Pay Centre.

The think tank called on the Government to take "radical action" on top pay, warning that the gap in wages was creating a "deep sense of unfairness".

The research showed that in 1998, the average chief executive of a FTSE 100 company was paid 47 times the pay of their average employee.

An analysis of six major firms in 1980 found that chief executives were paid between 13 and 44 times that of their average employee.

The figure has now increased to 143 times, although in some companies, top executives were paid hundreds times the pay of their average employee, said the report.

The study was published following figures from the Office for National Statistics last week which showed that average pay has fallen by 0.2% over the past year.

High Pay Centre director Deborah Hargreaves said: " While Government figures confirm that wages for ordinary workers keep falling, it's clear that not everyone is feeling the pain.

"When bosses make hundreds of times as much money as the rest of the workforce, it creates a deep sense of unfairness.

"Britain's executives haven't got so much better over the past two decades. The only reason why their pay has increased so rapidly compared to their employees is that they are able to get away with it.

"The Government needs to take more radical action on top pay to deliver a fair economy that ordinary people can have faith in."

TUC general secretary Frances O'Grady said: "Top bosses across Britain have been holding down the wages of their staff but they've shown no such restraint when it comes to their own pay packets.

"Unless we get to grips with growing pay inequality, the same old rich elites will hog the benefit of economic growth for themselves while millions of working people will miss out."

Paul Kenny, GMB general secretary, said: "This is a blatant case of market failure as these managers are not worth this money. The top managers help themselves to vast sums simply because they can do so and no one stops them."

The High Pay Centre compared pay for FTSE 100 chief executives recorded in company annual reports, to figures for average pay at each firm, provided by Pensions and Investment Research Consultants.

A spokesman for the Department of Business, Innovation and Skills said: " The Government has introduced comprehensive reforms to give shareholders more powers in order to restore the link between top pay and performance, which in recent years has become excessive and increasingly disconnected.

"In October 2013 new laws reforming the governance of top pay came into force, boosting transparency by arming shareholders with more information and giving them the power to hold companies to account.

"Business Secretary Vince Cable also wrote to all the members of the Remuneration Committees back in April urging restraint, and while we will need to wait until the end of the AGM season before we can reflect on the full impact of these actions, many firms have already seen top pay voted down."