The Royal Mail is launching a major crackdown on bullying in the workplace after hundreds of complaints by members of its staff.
Demobbing after Second World War created a macho culture
Chairman Allan Leighton admitted that the Royal Mail was "blighted" by a macho culture and said physical and mental abuse were common.
There is more bullying and harassment than in any other company in the country, Mr Leighton admitted.
Workers found guilty face disciplinary action and could get the sack, he said.
Around 20% of staff complaints every month are linked to bullying or harassment, Mr Leighton said.
"It's a blight. It's not management to colleague, it's more colleague to colleague," he said.
"Sexual harassment is rife. Until we deal with all of these things we can't move on as a company."
The Royal Mail's macho culture stemmed from demobbing after the Second World War, when many ex-military servicemen joined the Post Office.
"Nobody's ever taken a stand against it in the past, it's been endemic. It's the one thing at the end of my tenure at Royal Mail I want to get right," Mr Leighton said in an interview to the Yorkshire Evening Post.
The Royal Mail launched a special helpline in April for workers to make complaints about bullying or harassment, and more than 1,200 formal complaints were lodged, although many did not result in any action or were resolved informally.
The helpline is open 24 hours a day, seven days a week, and is staffed by trained counsellors.
The Communication Workers Union (CWU) fully supported the company in backing a campaign it said it launched more than three years ago while setting up its own harassment hotline.
"In many case the bullies have pleaded ignorance or "fun". Neither of these excuses hold water any more," said CWU
general secretary Billy Hayes.
"All our members have the right to be treated with dignity and respect at work."