A fresh row over the earnings of company executives flared yesterday after a study claimed the gap between the average wages of directors compared with the lowest-paid workers in the UK is widening.

Research by the GMB union showed that directors and chief executives earned an average of £214,000, almost 20 times as much as waiters and waitresses, who were on just over £11,000.

The gap between the top and bottom earning professions widened from almost 19 times to almost 20 times over the past year, the study revealed.

Paul Kenny, general secretary of the GMB said some executives were actually earning up to 50 times the average wage of the lowest-paid workers.

"We are asked to believe that those at the top need to be 'incentivised' by multi-million pound pay packages to maintain a dynamic economy, while those at the bottom in the public sector must make sacrifices for the good of the economy.

"GMB members do not buy this logic. Those at the top are unnecessarily being paid too much and there is no evidence that there is any benefit from this except to line the pockets of an elite."

Directors' average pay was now over seven times the UK average wage of almost £30,000, while waiters and waitresses were only on just over a third of average earnings, the report showed.

Other high earners included brokers (average pay of £101,000), financial managers (£84,000), medical practitioners (£78,000), senior government officials (£69,000) and pilots (£65,000).

Low earners included school assistants (£11,400), playgroup leaders (£11,500), check-out staff (£12,200) and bar workers (£12,500).

The study of full-time workers in more than 300 professions showed that train drivers were the highest-paid manual employees, earning an average of £37,000.

The GMB called for changes to the tax system to "even out" earnings.