The fearless ferrymen of Dhaka's Buriganga river

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Media captionFerrymen have to jostle for position in the queue to pick up passengers

Rush hour in the Bangladeshi capital sees thousands of Dhaka's commuters boarding small wooden boats to cross the busy waters of the Buriganga river, one of the most dangerous waterways on Earth, especially for the ferrymen.

"To do this you need all your strength and courage. If you lose your bravery then you are finished."

Ferryman Muhammed Abdul Loteef takes passengers and goods across a quarter-mile (400m) stretch of the Buriganga river every day.

It is hard physical work in temperatures of up to 40C - especially for a 70-year-old.

There are few bridges across the Buriganga river. For the 25,000 people who commute every day between the city centre and the residential areas on the other side, the sampans - small wooden boats, powered and steered by one oar - are a lifeline.

The ferrymen must negotiate huge gravel barges, cargo ships and passenger boats, which dominate the river.

"Every day here one or two boats capsize," says Loteef.

"Sometimes small boats go under the big boats and people die."

There are no emergency services here. If there is an accident, it is up to the other boatmen to come to the rescue.

One of Loteef's friend's boats was hit by a launch a few months ago, when it was fullly laden with nine passengers.

"Of them, I rescued eight," he said. "They found the (other) body three days later," he says.

"It is our duty to save our passengers. Sometimes we risk our lives to save passengers."

For that dedication, there is not much financial reward. It costs two taka (just over £0.01 or under $0.02) to cross the river.

To make enough money to support his family, Loteef has to make the crossing more than 60 times a day, and sometimes works into the night.

British ferryman Colin Window, a bridge officer on the Woolwich ferry across the Thames in London, is stunned by how hard his Bangladeshi counterpart works.

"He's been at it all day. He's had a small break I think for his prayers and that, but he's still powering backwards and forwards. He's 70 years old. He's unbelievable.

"These guys... are really pushing themselves to the limit every day. They must be a really hard, hard people here to be able to cope with this."

On one trip together, Mr Loteef and Mr Colin, as they call each other, have a close shave with a large boat.

"That would be a reportable near-miss on the river Thames," says Colin, amazed.

Like millions of Dhaka's other inhabitants. Loteef used to work on the land, but increasingly unpredictable weather has left many farmers unable to earn a living.

Bangladesh has always suffered from cyclones and flooding but storms have become more frequent and unpredictable and river erosion has accelerated.

Every day an estimated 2,000 people arrive in the city having left their villages.

Mr Loteef admits he finds it very hard to live in the city. But compared to many other ferrymen, he is doing well - he owns his own boat and he and his family have a room in one of Dhaka's hundreds of slums.

Many ferrymen have to rent boats some have to sleep on them.

"We have a saying, 'If God gave me wings on my arms I would go back to my village,'" says Loteef.

Image caption Sampan ferries have barely changed in thousands of years

He owns a small plot of land where he could still grow lentils, but that would not make enough money to support his family.

"We could make it work if we had two cows. If I had two cows I would not have to live in the city," he says.

But just one cow would cost Loteef more than he earns in a year.

"It's my own land and I want with my whole heart to be able to mark my father's grave," he stuttered, walking away to hide his tears.

For Colin, swapping the 1,000-ton Woolwich car ferry for a sampan for two weeks, to film a BBC Two documentary, was "extremely, extremely hard work".

He feels changed by his time in Bangladesh, and on his return to London he admits to constantly thinking about his time there "to try and make some sort of sense of the whole chaotic nature of what it was like".

"You just want to try and make sense of it so you can try and find a solution for some of them, which is what I'm trying to do."

His first solution was to buy two cows for Loteef, who has now moved back to his village.

Toughest Place to be a Ferryman is on BBC Two Sunday 26 August 21:00 BST. Watch online or catch up on the rest of the series via iPlayer (UK only) at the above link