Another said they were cancelling their payments to support Greenpeace in the wake of the disclosure and series of other damaging revelations of of disarray and financial mismanagement at the organisation, in documents leaked to the Guardian newspaper.

Greenpeace was last week forced to apologise for a “serious error of judgment” after it emerged that it had lost £3m of public donations when a member of staff took part in unauthorised currency dealing.

Each round-trip commute Mr Husting makes would generate 142kg of carbon dioxide emissions, according to airline KLM.

That implies that over the past two years his commuting may have been responsible for 7.4 metric tons of carbon dioxide emissions – the equivalent of consuming 17 barrels of oil, according to the US Environmental Protection Agency.

But Mr Husting defended the arrangement, telling the Telegraph that while he would “rather not take” the journey it was necessary as it would otherwise be “a twelve hour round trip by train”.

“I spend half my life on skype and video conference calls,” he said. “But as a senior manager, the people who work in my team sometimes need to meet me in the flesh, that’s why I’ve been going to Amsterdam twice a month while my team was being restructured.”

He said that from September he would switch to making the trip once a month by train due to “the work of restructuring my team coming to an end, and with my kids a little older”.

The head of Greenpeace in the UK on Monday denied that funding Mr Husting’s commute showed a lack of integrity.

Writing in a blog, John Sauven, executive director of Greenpeace UK, said: “As for Pascal’s air travel. Well it’s a really tough one. Was it the right decision to allow him to use air travel to try to balance his job with the needs of his family for a while?

“For me, it feels like it gets to the heart of a really big question. What kind of compromises do you make in your efforts to try to make the world a better place?

“I think there is a line there. Honesty and integrity to the values that are at the heart of the good you’re trying to do in the world cannot be allowed to slip away. For what it’s worth, I don’t think we’ve crossed that line here at Greenpeace.”

But Richard Lancaster, who said he had been volunteering with Greenpeace since the 1980s, responded: “I volunteer with Greenpeace but work in the commercial world and if I took a job in another country I’d expect to move to where the job is and if I couldn’t for family reasons I wouldn’t take the job – so I find Pascal’s travel arrangements almost unbelievable.”

Another respondent to Mr Sauven’s blog – which also addresses concerns over Greenpeace’s management – wrote: “So disappointed. Hardly had 2 pennies to rub together but have supported GP [Greenpeace] for 35+ years. Cancelling dd [direct debit] for while.”

Greenpeace campaigns to curb the growth in polluting air travel and end “needless” domestic flights. In a briefing on “the problem with aviation”, the group says: “In terms of damage to the climate, flying is 10 times worse than taking the train.”

Kumi Naidoo, Greenpeace’s top executive director, told the Guardian that while Mr Husting “wishes there was an express train between his home and his office… it would currently be a 12-hour round trip by train”.

“Pascal has a young family in Luxembourg. When he was offered the new role he couldn’t move his family to Amsterdam straight away. He’d be the first to say he hates the commute, hates having to fly, but right now he hasn’t got much of an option until he can move.”

Greenpeace argues that it does not want to “stop people from flying” but does “want to prevent the number of flights from growing to dangerous levels”.

It alleges that flying remains largely the preserve of the wealthy, citing a study showing “cheap flights haven’t created better access to air travel for the poor; they’ve just allowed people with more money to fly more often”.