In the chaotic heart of downtown Dhaka, the 19-story Brac building - home toone of the world's largest NGOs, the Bangladesh Rehabilitation Assistance Committee, an organisation so powerful that it is commonly termed Bangladesh's second government - casts a shadow over one of the city's largest slums. From the top floor, the slum looks like a ramshackle maze of corrugated iron and tarpaulin. But a short boat ride across the river reveals a neighbourhood of neat interlocking streets dotted with open shopfronts, selling everything from firewood to hot cakes, and with centres providing health and education programmes to its 300,000 inhabitants.
Most of the small enterprises here have been funded by Brac micro-finance loans. The slum's school is run by Brac-trained teachers using Brac textbooks. More than 200 Brac-trained health volunteers dispense medical services. Down the road is the Brac University, and a Brac bank sign is just visible across the street.
With an expenditure of £160m, a staff of 108,000 and services that reach more than 110 million people across the country, Brac has grown from a small relief operation into an organisation globally unsurpassed in the scale of the programmes it provides to some of the world's poorest people.
In its 35-year history, it has organised nearly 7 million landless poor into 239,000 village organisations and distributed more than £2bn in micro-finance loans.
Brac's vocational programmes and micro-financing have created in excess of 6m new jobs, its health services reach more than 100 million people every year, and around 1.5 million children are educated in its 52,000 schools. Its belief that climate change and rising sea levels will become the greatest obstacle to raising Bangladesh out of poverty has led to a social forestry programme that planted more than 15m trees in 2007.
"If 25% of Bangladesh is going to be underwater by 2100, then this presents the greatest challenge we have ever faced, and one that I think Brac will play a great role in finding solutions for," says Fazle Hasan Abed, who gave up a promising career in an oil company to help start Brac in 1972 and now, in his role as Brac chairman, is arguably one of the most influential men in Bangladesh.
The NGO's exponential growth is in part to do with the failure of Bangladeshi administrations to provide services for the millions of landless poor, but Brac has also proved to be good at making money. In the 1980s, it saw that the private sector was unwilling to provide support for the growth of small enterprise and stepped in to fill the gap. It now generates around 70% of its own income through a huge array of Brac-branded enterprises.
Following its meteoric rise in Bangladesh, Brac now believes it can replicate its work and influence in other developing countries across the world and solve some of the development dilemmas still left unanswered by northern NGOs.
"As a southern NGO, I think we have a different approach to development," says Brac's executive director, Mahabub Hossain. "We understand poverty because our country is, in many ways, defined by it, and we understand poor people's aspirations and needs. I think that, more than NGOs from the north, we are able to join up the dots."
Hossain says Bangladesh is now a fundamentally different country to what it was pre-Brac. "We are slowly proving it's possible to fight and win the battle with poverty here in Bangladesh," he says.
But Brac's swelling economic clout and increasing monopolisation of Bangladesh's development sector is causing concern in some ranks. There are accusations that Brac is acting like a parallel state, but one that is accountable to no one.
"Brac is an incredibly effective organisation, but it is at the stage where it is basically unchallenged," says Khushi Kabir, one of Brac's first employees and now the head of Nijera Kori, an anti-poverty NGO. "Government dependency on its services has grown to the extent that they almost can't run the country without it."
One area causing concern among NGOs such as Nijera Kori is Brac's environmental record, especially around the promotion of hybrid crop seeds to the millions of farmers taking out Brac micro-finance loans in Bangladesh's rural communities.
Brac moved into hybrid seed production in the 1980s, working first with Chinese seed producers to provide poor farmers with high-yield hybrid rice and maize seeds. Now teams of Brac scientists make their own in two Brac seed production plants. So far, it has cornered much of the hybrid seed market in Bangladesh.
The Bangladesh government has also heavily promoted hybrid seed planting, and aims to boost hybrid seed production from 250,000 hectares in the last planting season to 1m hectares in 2008. Brac and the government are working hand-in-hand to promote the usage of drought-resistant and flood-resistant hybrid seeds developed by international multinationals.
In December, two groups - Nayakrishi Andolon, a movement of 100,000 farmers, and the Ubinig social policy research organisation - accused Brac and the government of being "unethical" and dishonest in their promotion of hybrid crops.
"A group of seed dealers and micro-credit based NGOs are active [in the introduction of hybrid seeds] and are taking advantage of the natural calamities and disadvantaged condition of the farmers. These activities are totally unethical," says Ubinig executive director Farida Akhter, who claims that Brac is complicit in deceiving farmers about true production costs of hybrid seeds and inflating predicted crop yields.
The two groups say Bangladeshi farmers have enough of their own high-yielding varieties of aman and boro rice, which need to be protected and promoted.
"The total agricultural system is now under threat," says Akhter, who blames the promotion of hybrid crops for Bangladesh's increasing mono-crop rice culture. "Due to irrigation for boro rice cultivation through extraction of underground water, the water table has gone down. There are arsenic problems in drinking water, and desertification in the northern region of the country has been intensified."
More damningly, Nayakrishi Andolon and Ubinig also accuse Brac of linking access to micro-finance loans with the purchase of a particular hybrid rice seed, along with fertiliser and pesticide.
It is a claim Brac denies. "Our borrowers always have a choice," says Hossain. "They can either use our seed or not, but the simple fact is you can get twice as much profit from a hybrid rice or maize seed than you can from traditional strains.
"Our population has trebled in the last century, the land is limited, there are more floods, more cyclones, and more of the land we have is getting diverted for urbanisation. There is a huge national food gap. Development is about choices. There is a trade-off in everything we do, and there is an urgent and persistent need for food that we feel we have a responsibility to find solutions for."