In her 20 years as a doctor Ashwaq Muharram has never seen things so bad.

"I'm seeing the same thing I used to watch on TV when the famine unfolded in Somalia," she tells me. "I never thought I would see this in Yemen."

For years Muharram worked for international aid organisations, but most of them left when the fighting began in March 2015, and those that remain have drastically curtailed their activities.

So now she distributes medicine and food out of her own pocket, using her car as a mobile clinic.

I spent two weeks with Muharram, visiting towns and villages near Hudayda, and witnessing things that I too never thought I would see in Yemen.

Hudayda, controlled by Houthi rebels who took over the most of the country in 2014, was until recently the entry point for 70 per cent of Yemen's food imports. Now, not only is it under blockade, it has been pummelled by airstrikes carried out by the Saudi-led coalition - the port itself smashed, an entire tourist resort on the beach completely destroyed.

The bombs and the blockade pose a double threat to Muharram's patients.

"If you don't die from an airstrike, you're going to die from being ill and from starvation," she says. "And the hardest way to die is dying from starvation."

Having loaded up the car with medicines, we drive to Beit al-Faqih, 100km (60 miles) south-east of Hudayda. The village was once prosperous, growing bananas and mangoes for export but today the exports have stopped, most workers have lost their jobs, and the fruit we see loaded on to donkeys by colourfully dressed women is for most Yemenis simply unaffordable.

Hudayda, controlled by Houthi rebels who took over the most of the country in 2014, was until recently the entry point for 70 per cent of Yemen's food imports. (Photo: Reuters)

It is here that we meet a mother with a lactose-intolerant toddler, Abdulrahman, who weighs no more than a six-month-old baby.

"How old is he?" I ask her.

"18 months," she says. "He should be walking and talking by now."

She immediately breaks down into tears.

Abdulrahman needs a special type of milk that was once available everywhere in Yemen but has not been seen since the destruction of the port at Hudayda and the start of the blockade.

"We looked in every single pharmacy. All said it was nowhere to be found," says the mother.

Muharram tells the mother she will help her - before quickly realising this is a promise she may not be able to keep. She knows the boy will die without the milk, but getting hold of it will be a huge challenge.

"I've myself looked for this milk before, and it is nowhere to be found," she says.

Her own family has faced similar problems. After the war began, her husband fell ill and his heart began to fail; it was a heart infection and he was in urgent need of medication.

"I ran into Sana'a's main cardiac hospital, but as a doctor I knew what they were about to tell me - that they were out of supplies, and there was nothing they could do to help me," she says.

"I'm a doctor myself, my husband was dying in front of me and there was nothing I could do…"

Muharram breaks down.

Muharram: "I am tired as a doctor, as a mother, as a wife"

Her husband eventually left for Jordan, taking their two children with him to safety. They had already stopped going to school.

Driving back into Hudayda, tents line the pavements. Out of the window, I can see a man having a shower - with his clothes on - in the middle of the street, as barefoot children run around him, chasing one another. These are Yemenis who have fled to Hudayda from areas where the conflict is at its fiercest.

Travelling with Muharram from one village to the next, again and again we come across children suffering from severe acute malnutrition. (Photo: AP)

"The rich are now the middle class, the middle class are now the poor, and the poor are now starving," says Muharram.

"Some of these people had a life like you and me, and now look." She points at the people on the pavement.  "They have lost everything."

We stop to talk to a mother we have spotted on the street with three children.

She says the family once lived in Haradh, near the Saudi border, far to the north. They spent months in a refugee camp with little access to food or medicine, but then the camp was bombed. The woman's husband died in the attack.

As we sit on the pavement talking, coalition jets return, flying low above us.

Yemenis are trapped. More than three million people out of a population of 27 million have left their homes. Meanwhile, all ports have been closed by the Saudi-led coalition, preventing anyone from leaving. What's more, many countries that once welcomed Yemenis without a visa have since closed their doors to them.

Travelling with Muharram from one village to the next, again and again we come across children suffering from severe acute malnutrition. To put it bluntly, they are starving.

Malnourishment affects the immune system and makes children far more likely to fall ill. But at the same time it is becoming more difficult for them to get treatment. Many of the country's hospitals have had to close, either because of bombing or the lack of medical supplies.

The children's ward of Hudayda's central hospital is so full, there are two or three children in every bed.

We meet four-year-old Shuaib, whose grandfather has borrowed money from neighbours to travel to the hospital. The boy has been suffering from diarrhoea and fever, but doctors have had to tell the grandfather there is nothing they can do. "None of the antibiotics we have can treat the kind of bacteria he has," the hospital manager tells us.

As Shuaib lies there, his body growing colder by the minute, his grandfather holds his hand and weeps.

An hour later, Shuaib is dead. I watch as the grandfather, silently crying, covers his little body with his headscarf and carries him home to the boy's mother.

Yemen is a country under siege. Two years ago, Houthi rebels and their allies - an army faction loyal to former president Ali Abdullah Saleh - took control of most of the country, including the capital, Sana'a. The government was forced to flee. Saudi Arabia says it intervened at the request of the exiled Yemeni government. For 18 months the Saudi-led coalition backed by the US and the UK has been at war with the rebels.

Muharram herself is inconsolable. "Who is responsible for Shuaib's death?" she asks. "The war is responsible! But he will be considered a victim of hospital neglect. Thousands like him are dying. Do they have to be killed by an airstrike to be acknowledged as victims of this war?"

As we leave the hospital, news arrives that a hospital run by Doctors Without Borders (MSF) in the nearby city of Abs, has been shelled by coalition planes.

"They are bombing hospitals, why?" Muharram fumes. One reason is that Saudi Arabia accuses Houthi rebels of using hospitals to store arms.

The next day, I visit the MSF hospital. As I walk through the ruins of the children's ward, I find a scene of devastating poignancy - a paper party hat and the remains of a birthday cake and candles scattered across the floor.

"The children were having a birthday party before the airstrike hit," explains Dr Yahya al-Absy, the hospital manager.

In total, 19 people died in the strike - and the Abs governorate no longer has a hospital. In a statement, the Saudi government denied deliberately targeting civilians and humanitarian supplies. It also said it was the single largest donor of humanitarian assistance to Yemen.

The next day, Muharram finally receives some good news. A friend has found a way, at considerable cost, to get young Abdulrahman some life-saving milk from Saudi Arabia. Six days later, Muharram receives it and immediately rushes to his house.

Having witnessed nothing but despair for two weeks, it is incredible to see, at last, one happy ending. Abdulrahman takes his milk bottle and swiftly drinks it to the last drop, his mother crying as she watches.

"You've brought happiness into my home" she tells Muharram, wrapping her arms around her in a loving hug.

Though Ashwaq Muharram was able to save a child's life, more than million other children continue to starve across Yemen.

20 out of 22 governorates are on the brink of famine. Unless something is done very soon to end their suffering, the country could lose an entire generation.

(Watch Our World: Starving Yemen on BBC World News on Saturday, September 24 at 5pm IST, 1130GMT and Sunday, September 25 at 10am IST, 0430GMT.)