The green movement is "out-of-touch, ineffective and bureaucratic", according to the campaigner who spent a decade leading Friends of the Earth in the UK , which celebrates its 40th anniversary on Wednesday.

"Worryingly, in every major green group, managers, administrators, communicators and fundraisers outnumber campaigners and researchers. Interminable meetings, not action, are the order of most days," wrote Charles Secrett, FoE executive director until 2003, in an article for the Guardian. He estimates UK groups like FoE, Greenpeace, RSPB and WWF, which have millions of members, spend over £100m a year. His comments have drawn an angry response from those leading today's groups.

With climate change having dropped down the international political agenda, and the global financial crisis prompting leaders and businesses to question green spending, the environmental movement is at an impasse, argued Secrett.

He later told the Guardian: "The evidence of failure is there for all to see, as environmental problems are getting worse, not better." Previous dips during recessions have seen the movement bounce back stronger than before, he said, but warned: "It is very tough now. There is no time left as the degradation of the environment has reached a tipping point."

Secrett praised new groups like UK Uncut, which has taken direct action on tax avoidance, and online campaigns like 38 Degrees. But he said groups, new or old, running their own single-issue campaigns in parallel would never achieve the critical mass needed to push humanity onto the path of sustainable development, by tackling global warming and the loss of habitats and the animals and plants in them.

"If millions of people acted to hold politicians to account, that push would happen," he said. "There is a crucial role for the environmental movement now in building a consensus for change. We can't rely on politicians and business people to do that." But he said current campaigners were too often "conservative and unimaginative", adding "ambition is lacking through the fear of being seen to be too political".

Secrett's comments prompted a strong reaction from the groups criticised, many of whom have been rethinking their campaign strategies this year.

Ben Stewart, the head of media at Greenpeace, said: "I suppose I'm one of the PR people Charles is talking about. Right now I'm aboard one of our ships somewhere off the coast of Greenland where we've been hanging off an oil rig and stopping risky deep water oil drilling for several days. We've had 20 people arrested, more than half of whom are still in jail, and I know they're very grateful for the staff back home, including the fundraisers, who made our campaign out here possible."

The current executive director of FoE, Andy Atkins, firmly rebuffed the criticism: "We're not afraid to look at what we need to do differently: for 40 years we've been evolving so we keep winning campaigns. But some things haven't changed – FoE was a campaign-led organisation when we started in 1971, and we remain so today. Together with our supporters we've been winning real victories [such as] getting the world's first law to limit climate emissions, here in the UK, in 2008."

Other NGOs defended a more subtle approach to campaigning. Martin Harper, RSPB conservation director, said: "Shock tactics have their place, but no matter how loudly you shout, you will become background noise sooner or later. The most successful modern NGOs are those that know when to be a thorn in the side, and when to be a constructive partner. The RSPB is in the day-to-day job of conserving wildlife – and to do that we need to work closely with government and industry on a range of issues. "

However, Secrett's attack was supported by some environmentalists. Author Mark Lynas said: "I agree the green movement is stuck in a rut, but I think the problem is deeper than mere professionalisation and endless strategy meetings in corporate NGO head offices.

"Many 'green' campaigns, like those against nuclear power and GM crops, are not actually scientifically defensible, whilst real issues like nitrogen pollution and land use go ignored. The movement is also stuck in a left-wing box of narrow partisan politics, and needs to appeal to a broader mass of the public who are simply not interested in organic farming and hippy lifestyle choices. It needs to re-engage with science, as well as with the general public, if it is to remain relevant to the 21st century."

Secrett's intervention also echoes comments made by another senior green figure, Jonathon Porritt, who earlier this year accused the green NGOs of "betrayal" over their lack of opposition to the proposed sell-off of public forests, now abandoned. "It demonstrates to me how completely out of touch our environmental NGOs have become," he said.