Adam Crozier has said Royal Mail procedures will be reviewed
A television documentary allegedly showing fraud and theft taking place in a London Royal Mail sorting office was "exaggerated", said the firm's boss.
Chief Executive Adam Crozier said the Channel 4 programme did not represent a fair reflection of the service.
But he admitted that some areas of "wrongdoing" had been highlighted, and that if the claims prove to be true he will not hesitate in sacking workers.
In particular, he was concerned at the use of temporary staff from agencies.
Disciplinary investigations have been launched against a number of postal workers as a result of the Dispatches programme, broadcast on Thursday night.
The documentary's makers alleged that they had produced a "shocking expose" of far-reaching ineptitude in the Royal Mail, after an undercover reporter got a job with the service in Paddington.
The reporter claimed to have witnessed credit card theft, untrained staff who did not know where they were going delivering mail, and registered post discarded on the sorting office floor.
The "damning catalogue" also alleged that machinery was chewing up letters which contained money and that managers had to pay staff "ghost overtime" to get them work a full eight hour day, otherwise they would go home early.
Mr Crozier said he recognized that some Royal Mail customers will be dismayed at what they saw in the programme, but procedures and practices will be reviewed and action to improve the service will be taken.
"The quality of service Royal Mail gives is the most important thing for the company. There will be a particular focus on security and the recruitment, vetting and training of temporary staff," he said.
The Royal Mail's chief executive added that the programme had been made last autumn when London had been affected by industrial action, while the organization's modernisation programme began to take hold last January.
"A huge effort is under way to eliminate outdated and restrictive practices and significant progress is being made.
"The programme showed some of the inefficiencies that have already been largely removed," Mr Crozier said.
He predicted that the number of first class letters arriving on time will reach 90% for the current financial year, but he accepted that this was below the target figure of 92.5%.