The voluntary sector is not always a place that puts money where mouths are. Some of the most vociferous anti-poverty organisations pay their own staff little more than the minimum wage; disability charities lambast the inaccessibility of corporate websites while neglecting their own; and the environmental sector preaches the importance of bio-diversity while conspicuously failing to deliver human variety in the make-up of its own workforce.
According to BTCV, only 1 per cent of staff in environmental voluntary organisations are from an ethnic minority. While seven out of 10 black Britons regard looking after their local environment as 'very important', they are much less likely to be involved in community work than whites.
The environmental volunteering charity is determined to do something about this. It has already succeeded in increasing the proportion of staff from BME groups among its own workforce from 3 to 5 per cent. It is also striving to include asylum seekers, refugees, immigrants and travellers in its volunteering work. But it has even more ambitious horizons. The charity wants staff in its 200 offices across the country to reflect the diversity of the communities they represent, so that in mainly black areas, most staff should be black. And it thinks other environmental organisations should do the same.
The man behind this recasting of the organisation's aims and values is chief executive Tom Flood. At first glance he makes an unlikely champion of the under-represented. White, middle-aged, urbane and with a background in the corporate sector - he spent 14 years with 3M, the company that makes Post-it notes and Scotch Tape - he appears the consummate insider.
In fact, he is also a government favourite, having rubbed shoulders with the captains of industry as a member of Labour's New Deal Taskforce.
Yet, he describes his cultural revolution at BTCV as a "very personal journey". For Flood, in common with many of the people he is trying to involve in volunteering, is an immigrant.
Born in horseracing country of Curragh in Ireland, he came to England in 1972 at a time when being Irish possessed none of the cultural kudos it does now. It is an experience that still resonates. "You have to recall it was when the IRA were actually bombing here, and being an Irish citizen was not easy," he says. "I had a thick Irish accent. I didn't hide my culture, I never have. And I was the butt of jokes, some were quite offensive, some were not intended to be offensive but actually were. I think it gave me a lot of understanding of what it is like to be absolutely different - if your colour is different, for example, or if you're economically disadvantaged so that you can't take advantage of all the things you see in society."
But while Flood may be sensitive to the feelings and needs of the "bruised" and excluded communities he is trying to tap into, the rest of the environmental sector is not, it seems. He says that environmentalism deserves its white and middle-class reputation. "It's a very white tradition, very Victorian," he says. "Bio-diversity's scientific community would be mainly male and completely white. I think the probability is that many of those people have never experienced multi-cultural Britain. They live lives that are relatively narrow, quite insulated and probably protected.
"A wildlife trust or a nature reserve holds no relevance for some of the communities that I talk to. Many of the newer communities we are talking to are based in urban Britain, they probably don't use open space and countryside in the way the white community traditionally has, and they lead lives which are very disadvantaged in very crowded areas."
And while BTCV has made a deliberate attempt to break out of the white environmental ghetto, it has not been a smooth process. Flood says many deprived communities did not initially welcome its arrival among them: "These communities are innately suspicious of mainstream environment organisations - and with good reason. You've got to show humility to win trust."
The charity has had to advertise three times in some areas to get staff and invest heavily in training because the people it wants do not have the requisite skills. But Flood says he is determined to change BTCV for good: "It will be patchy, I can't guarantee exactly how it's going to take shape. But if you look at this organisation five years down the line, it will be fundamentally different," he says.
There have also been internal tensions within an organisation that has historically been a bastion of white, middle-class Britain. The charity's traditional step of closing over Christmas has had to be revised for workers who don't celebrate the festival. And it is trying to find space for prayer rooms in its offices or, failing that, educating staff that some Muslim colleagues will be unfurling a prayer mat next to their desk several times a day.
Some of the charity's older staff have reservations, Flood concedes, about whether BTCV's core conservation work "is getting lost in the dream".
His reaction is understanding but unyielding: "I have said to people, we will be this organisation, and that I hope everybody feels that's where they want to be. But if it isn't what you want, then your choice, I'm afraid, is to go."
For Flood himself this may well be "the last big adventure" in his 18-year journey at BTCV. Now in his late fifties, the thick home-grown accent has given way to a soft Irish burr. "I'm getting to a point where this is the big thing I want to get right. If we do, we'll be an organisation of such diversity, we'll have forgotten why it was ever a problem."