Two senior flight operations inspectors have claimed they were forced out of the Civil Aviation Authority after raising concerns that job cuts had put passengers at risk.

John Baker and Terry Neale, who served with the air safety regulator for a total of 40 years, told an employment tribunal that CAA managers changed their working conditions and downgraded their performance ratings after they expressed concerns to the board about dwindling numbers of qualified staff.

Both were inspectors who oversaw the training of pilot instructors and examiners at British airlines and flying schools.

Baker, a former Royal Navy pilot, said the CAA “denigrated safety concerns” he raised in an email to the then chief executive, Andrew Haines, and other board members, referencing fewer experts overseeing aircrew training.

In a witness statement submitted to the tribunal in Croydon, south London, he said it was “the culmination of concerns expressed by me to CAA management during its transformation programme”, and warned “the number of training inspectors, flight examiners and licensing standards inspectors are now well below the critical mass where we might hope to influence the standards across the industry … with any real effectiveness”.

Baker sent the email in February 2015, days after watching footage from a plane crash in Taiwan, where 43 people died due to pilot error after an engine failure. He said he had seen pilot instructors at a major UK airline poorly trained to deal with such a scenario, “highlighting the potential for a similar mishap to occur in the UK … I and my colleagues were warning of an increased risk to the travelling public”.

An internal review had since confirmed he was not alone in having safety concerns, Baker said. It found 20% of 289 staff respondents agreed that they “felt confident our [safety and airspace regulation] activities are currently sufficient to assure ourselves that we are protecting the safety of the public”.

Baker claimed he was told he could no longer work at home or do flexible hours in a role that was a long distance from his home, “making the job untenable” before he resigned in 2015.

In a written statement, Neale said he resigned after “victimisation” following “the raising of a serious concern for the safety of the travelling public to the executive committee of the CAA”, in a presentation that pointed out the number of inspectors in his section had dropped from eight to two, plus two part-time.

He claimed the meeting “triggered a series of recriminatory actions”, including loss of flying time, which he said was “highly incongruous for a regulator which encourages the aviation industry to have an open reporting ethic”.

Cross-examining, lawyers for the CAA challenged Neale’s account of his treatment, citing emails showing his flying activity had stopped before the board meeting.

They argued he had not made a public interest disclosure, as Haines and the board were well aware of “people in the ranks expressing concern about staff numbers”, and there were no notes of claims he had made in the meeting, which he had been invited to address on the subject of automation in aviation.

The CAA denies constructive dismissal in both cases. Neale is claiming £367,ooo in compensation, and Baker is seeking £181,000. The hearing continues.

The regulator underwent a “transformation programme” after Haines took over in 2009, with the overall wage bill slashed. According to the Prospect union, a significant number of highly trained and experienced safety inspectors left the CAA, often signing confidentiality agreements.

The CAA has said independent international safety audits showed it was consistently performing to a very high standard, in compliance with its regulatory duties, and that it had consistently protected frontline safety roles.