The head of the Scottish government's green watchdog is under fire for taking climate-wrecking flights last week.

Sir Ken Collins, chairman of the Scottish Environment Protection Agency (Sepa), flew from Edinburgh to Inverness on Wednesday and then on to Orkney on Thursday. This has infuriated some of his staff, who say the flights are "very embarrassing" for Sepa.

The Sunday Herald revealed last November that Sepa officials had taken 1500 mainland flights in the previous year, more per member of staff than most other public sector agencies. This prompted Sepa's chief executive, Campbell Gemmell, to launch an overhaul of travel policy with the aim of slashing internal flying by half within a year.

But now Sepa insiders are angry that Collins, a former Labour MEP, doesn't seem to have got the message. "While it is right that staff should look closely at their requirement to fly it is particularly galling when staff in the north of the country are required to sit on a train for hours when the chairman is happily flying to and fro," complained one.

Insiders point out that Collins could have made his appointment to meet staff in the Dingwall office at 1pm on Wednesday by catching the 8.35am train from Edinburgh. They also say that he has travelled by air to Exeter, London, Wick, Stornoway and Shetland this summer.

According to government figures, short-haul flights are by far the most polluting way to travel. Per passenger they emit three times more CO2, the main cause of global warming, than trains.

"It is important that Sepa's chairman sets the best example when and wherever he can," said Friends of the Earth Scotland chief executive, Duncan McLaren. "There can be very few times where one could say an internal mainland flight was an environmentally friendly option."

But Collins argued that it was important for him to "get out there" so he was not seen by staff as a "remote figure". In the last eight years he has made a point of personally visiting all of Sepa's 22 offices to listen to staff's views.

"Opting for flights so I can visit some of our mainland and island offices in one trip is the best way to do this," he said.