The BBC has severely damaged its international reputation by its handing over large payoffs to senior staff, according to a committee of senior MPs.

The public accounts committee (Pac) also accused the BBC Trust, the corporation's governing body, of "sitting on its hands" while the payoffs were being made, and challenged the accuracy of some of the evidence given to the committee by corporation executives.

Monday's Pac report follows committee hearings in which five current and former executives including Lord Chris Patten, the BBC Trust's chairman, and Mark Thompson, the former director general, attempted to blame each other for more than £2m of payoffs for senior BBC managers.

Among the payouts given to senior staff were £470,000 to former director general George Entwistle after only 54 days in the job and £680,000 to former chief operating officer Caroline Thomson. Deputy director general Mark Byford departed from the BBC with a total payout of £949,000.

Margaret Hodge, who chairs the committee, said some of the justifications for the payoffs had been "extraordinary".

"The BBC is the world's leading public sector broadcaster, but recent revelations over severance payments to departing senior managers have put its reputation at risk," she said.

"150 senior managers between them received payments totalling £25m. We were dismayed to find that many of these individuals received 'sweeteners' in their severance packages that were far larger than the sums to which they were contractually entitled."

Hodge said there was "a failure at the highest levels of the BBC to challenge payments to senior managers and what appears to have been a culture of cronyism that allowed for the liberal use of licence fee payers' money".

The committee heard evidence in two sessions from BBC figures, including outgoing HR boss Lucy Adams, the current director general Tony Hall and former director general Mark Thompson.

Adams has admitted making a mistake in her evidence. She first told MPs she had not seen a note detailing plans for payoffs to Byford and marketing boss Sharon Baylay – but now admits she helped write it.

The report said the committee "remain concerned about the veracity of other parts of the oral evidence we heard".

In a report published in July, the NAO found that the BBC had paid £25m in severance payments to 150 senior staff. Furthermore, it showed that the BBC had paid 14 staff more than it had been contractually obliged to.

The top 10 payments amounted to £5,298,900 – 20% of the total.

The NAO also discovered instances in which departing managers were given large payoffs even after they had found work elsewhere, and examples of staff who were offered consultancy roles at the time of their departure.

Thompson, who is now the chief executive of the New York Times, released a statement rebuffing claims of wrongdoing by former BBC staff.

"The members of the Pac are entitled to criticise the result, but the decision to make the settlement was made in an entirely proper and transparent way.

"Despite some inflammatory language in the Pac report, there is absolutely no evidence of any wrongdoing by anyone at the BBC in relation to these severance payments."

A BBC spokesman said: "One of Tony Hall's first acts on his appointment was to cap payments at £150,000 – the committee welcomed his decision."

Responding to the criticisms in the report about the corporation's governance, he said: "There needs to be absolute clarity over the responsibilities of the Trust and the BBC executive and we have already acted and announced a range of changes to deliver that."

A BBC Trust spokeswoman said the Pac's work had "helped inform" the corporation's plan to simplify the way it was run which were announced last week.

"We have already announced measures that address the committee's call for more rigorous scrutiny of the BBC's performance and clarify the Charter's requirement that the BBC executive manages the BBC while the Trust represents the licence fee payer," she said.