The number of workers in the UK earning six figure-salaries has risen by nearly one half over the past four years.

The Inland Revenue estimates that 326,000 people will earn at least �100,000 before tax this year.

In 1998-99, the number of workers earning that amount was 222,000.

The figures show that this year, 285,000 of the highest earners will be men, and 41,000 women.

Average wage

Alastair Hatchett, of Incomes Data Services, said the data reinforced observations that the number of people earning the highest salaries has been growing.

It's in the City where this money is being earned, as well as by directors

Alastair Hatchett Incomes Data Services

He told BBC News Online: "This has been a tendency over the last two decades.

"It has meant that the overall distribution of earnings has stretched further.

"And it means that the number of people earning below the average wage has grown slightly."

City bonuses

Last year, the UK's average national wage, calculated as a mean of overall salary data, was �23,607, the Office for National Statistics said.

David Beckham earns �11m a year

Yet more than 60% of workers earned less than the average salary.

The average income figure was being skewed in particular by the large salaries given to bankers and stockbrokers, Mr Hatchett said.

"It's in the City where this money is being earned, as well as by directors," he said.

"And a large proportion of it is being paid in bonuses."

Pay hikes

Even though there have been job losses in London's financial centre, employees were moving to other firms, and bonuses were still being paid, Mr Hatchett added.

Big UK earners

Bernie Ecclestone: �788m Madonna: �30m JK Rowling: �24.8m Sir Paul McCartney: �20.5m Sir Anthony Hopkins: �19m The Queen: �15.2m Source: Sunday Times 2001 pay list

Footballers are among the country's biggest earners.

England captain David Beckham recently signed a new contract with Manchester United which will take his earnings to �11m a year.

In the business world the chief executive of BP, Lord Browne, saw his salary rise 58% last year to more than �3m.

Gender gap

The Inland Revenue's figures show that in 1998-99, 13.8% of the highest earners were women.

This year, 14.2% of those getting six-figure salaries will be women.

Mr Hatchett said he thought it would become increasingly difficult for women to close the pay gap.

"At the top end of male earnings they keep moving the goal posts," he said.

"Every time there's any closing of the gap, top male earnings rise."