The chief executive of the Financial Times has returned a substantial part of his £2.6m pay packet after a backlash from reporters who argued his high income was unjustified.

Staff had been due to hold a union meeting on Wednesday afternoon to discuss John Ridding’s pay, arguing that it had risen by 442% since he joined the company in 2006.

“John Ridding was paid 100 times the salary of a trainee journalist in 2017,” said one union email to staff, obtained by the Guardian. “His pay rise of more than 25% last year was more than double the median FTSE 100 chief executive pay increase last year, which, as we report today, was a greedy 11%.

“Please come and air your views about John Ridding’s pay and what you think should be done about it.”

Shortly before the meeting, Ridding sent an email to all staff announcing a climbdown, promising he would give up the equivalent of £510,000 of his salary. Since tax has already been paid on it, about half of that sum will be returned to the company.

He said the money would be used to promote women’s careers and reduce the gender pay gap at the organisation. The median pay difference between men and women at the FT is 18.4%, compared with 8.4% at Guardian News and Media.

“For now, I have decided to reinvest into the FT the increase awarded in 2017, which is £510,000 before tax. The first call on these resources will be a women’s development fund to augment and accelerate our efforts to support the advancement of women into more senior roles at the FT and reduce the gender pay gap,” he wrote.

Ridding said his pay had been independently assessed and benchmarked with substantial performance-related incentives when the Japanese publishing business Nikkei bought the newspaper in 2015.

“While our performance has been strong, I recognise that the size of the consequent jump in my own total reward in 2017 feels anomalous and has created concerns. Many key decisions rest with me as CEO, but collective hard work at the FT underpins our success,” he wrote.

The company’s most recent accounts, published last month, show the company made an operating profit of £5.2m, although the FT said the accounts underplayed the real profitability.

The FT’s transition to a digital-focused publisher has been seen as largely successful, and the chief executive appeared to suggest the company’s ability to hit targets was responsible for his bumper income.

“Last year was a particularly strong year in which we significantly beat our targets,” he wrote. “Subscriptions increased by more than 65,000 to reach an all-time high of more than 910,000 and take us a big step towards our goal of one million worldwide paying readers.”

Ridding said his new pay scheme should take into account his income before Nikkei bought the company, which was approximately £1.6m in 2015.

The FT newsroom has a strong union presence and some staff are understood to be angered that the returned money is not being reinvested in journalism.