Surrounded by brown, fast-shifting water on all sides, the 40 or so families in the village-turned-island had received no food, no medicine and no news as to when they might be rescued.

"We're dying of hunger," shrieked the woman, Sughra Bibi, as volunteers on the boat handed over plastic bags of lentils and cartons of milk to the villagers who gathered around her. One of them shouted out: "We don't care if it's the chief minister or the prime minister, but no one is sending anything to us. We are only waiting for God's help."

Across a huge swathe of central Punjab, Pakistan's famously fertile agricultural belt, now besieged by unprecedented floods, such scenes are being played out a thousand times or more. While countless numbers have by now been rescued from the waters, hundreds remain cut off from dry land.

Both the rescued and the stranded are hot and angry, tired and bewildered, having seen their livelihoods destroyed and struggling now with just the barest of assistance from the authorities. Even if they had heard the news, few would have been moved by President's Asif Ali Zardari's belated return to the country and his appearance at a photo opportunity yesterday in the south, where he handed out supplies.

Here, amid the small villages west of the city of Multan, home of the country's Prime Minister, Yousaf Gilani, everyone tells the same story as to what happened four days ago: the waters came silently during the night, like a thief slipping into the village. Those who heeded warnings of the anticipated surge had gathered together what they could, and moved themselves to higher ground. Others awoke to find themselves scrambling for their lives amid a landscape of shimmering water where once there had been fields. All they could do was wait for the rescue boats.

The boat which The Independent accompanied flew the black and white banner of Jamaat-ud-Dawa, the supposedly banned Islamic charity, accused by the UN Security Council of being a front for militants who allegedly planned and carried out the 2008 terror attacks on Mumbai.

In this natural disaster, as in several before, the Lahore-based group has played a central role delivering aid, rescuing people and providing emergency medical help. With the army and civilian rescue teams utterly overstretched by the scale of the disaster – now estimated to affect a quarter of the country – the charity's efforts have been embraced by the public. When they deliver food or rescue somebody, they ensure that people know who is providing this help.

"We are taking out food to people who are stranded," said Navid Umar, a friendly but serious young man from Lahore, who was the group's leader. "We're doing 25 trips a day."

The journey to reach the stranded villagers cut through an unlikely landscape of flooded buildings and verdant date palms, half-submerged by the water, past houses on scraps of land where people lay on charpoy beds and waited for the water to recede.

Elsewhere, small groups struggled through the floods to try and reach help, belongings balanced on their heads, feeling their feet uncertainly in the current. At one point, a man guided his wife, who was covered in a bright white burqa, through a long stretch of water that came up to their waists. Children, oblivious to the nature of the crisis, splashed and played.

It was blisteringly hot, even by the furnace-like standards of a south Asian summer, and on one journey a young woman lifted into the boat to be transported to the "mainland" fainted from the heat. It was suggested that her family try and cool her down by fanning her, but the only thing to use was a slightly sodden Jamaat-ud-Dawa pamphlet, proclaiming the charity's good deeds. The family gladly took it and started to waft it back and forth in front of her face as she lay quietly, her head tilted back.

Aside from the heat, the rescue mission was made more difficult, said Mr Umar, by the likelihood of snakes in the water and the amount of weeds and debris that kept becoming entangled around the propeller shaft of the boat's outboard motor. He said that several times the boat had become grounded and that on one occasion they found themselves stuck on the roof of a flooded house.

In addition, yesterday was also the first day of Ramadan, the month-long fast during which Muslims are not permitted to eat or drink between sunrise and sunset. Islamic teaching makes exceptions for the ill, or else those involved in such emergencies, but the volunteers on the boat said they were observing the fast. Indeed, even though he was delivering food to those in need, Mr Umar appeared a little unsure whether they should actually be taking it.

"Are you fasting," he asked a little sternly of one man who was standing in dirty brown water up to chest. The man, seemingly bewildered, replied: "No, not in these conditions."

Mr Umar was not convinced and demanded to know why. The man sheepishly smiled and headed off with his bag of lentils.

Indeed, Mr Umar appeared to relish the challenge that confronted him and felt no need in any way to dilute his religious obligations. He said that on occasions he and his team had been unable to fulfil all of the five daily prayers according to schedule – catching up the missed one later, as is permitted – but often they would steer their boat towards a piece of land, get out and pray. Asked why a merciful God would permit such deadly, devastating floods, he replied without hesitation: "It is a test for the pious. For those who are not pious, it is a punishment."

While the men from Jamaat were at the forefront of the rescue efforts, they were not the only ones helping the needy of central Punjab. Civilian rescue teams were in attendance, as were the army and, rather incongruously, a group of adult, uniformed Scouts, complete with scarves and woggles.

While followers of Lord Baden-Powell may have had the best uniforms, it was the army that had the best equipment, and a large green truck of the 9th Balouch Regiment thundered through the flood waters, carrying people and sacks of food that had been donated by the local Lions Club.

"The water on this side is going down but on the other side it may be rising," said Mohammed Arshad, a 25-year army veteran, who was also not eating or drinking. "Just two days ago the water was up to the windscreen."

Yet while the water may be slowly receding, at least here, the anger and frustration of people is not. Tens of thousands of people, who had little before the floods arrived, have been evacuated, dropped off at emergency camps in Multan and nearby Muzaffargarh, or, more likely, forced to find shelter on the side of the road leading away from the floods where countless families are camped out. Elsewhere across Pakistan, more rain is predicted and several cities in the southern province of Sindh still risk having their flood defences breached.

About five miles from the floodwater's edge, a group of 38 families from Baseera, all of them kiln-workers, had taken over a sandy hillock. There was no water, no shade, and unlike other families who had managed to save their livestock – buffalo, camels and cattle – this community had just two tethered goats. Each family was occupying a tiny makeshift home constructed from two rope beds and a mat. "All we are left with is what you can see," said Mehboob Ahmed, one of the villagers.

Everyone agreed that they would return as soon as they could, as soon as the water that had taken their homes had gone. They also agreed that these terrible floods were like nothing anyone had ever witnessed before.

Except, perhaps, for Mallick Yaru. Across the string of besieged communities, people spoke of the elderly man who had witnessed the floods of 1929, which also devastated this area and other parts of the country. He was 85, 90 perhaps even 100 years old, they said, and he lived in a village called Chowkgodar, eight miles away, where he had built a mosque on land that he owned.