Some background to the problems facing patients with cleft deformities in Pakistan.

When she lifts her head, Bushra Zupfqr pulls her hijab over her face. She had enough of the stares a long time ago. 

She doesn't go to school. There's no point. All anyone talks about is the curse inflicted on her, the girl with no nose

Bushra, 15, spends her days cleaning the house and doing chores for her mother. She hides herself away from a world that only sees her disfigurement.

Her 12-year-old brother Abdul Wahid knows what it's like. While frontonasal dysplasia is  extremely rare, the cruellest blow is that parents with genetic susceptibility can have more than one child affected.

It's pitch black outside but the children have just arrived at the Cleft Hospital in the city of Gujrat in Pakistan after travelling 11 hours from a remote village to the north of Pakistan. They've come with a family friend. They speak Pashtun and they speak Urdhu in Gujrat. The family friend can speak both so he's been trusted with translation.

The man tells hospital staff the children's appointment is for the morning but they've come tonight because they didn't want to be late. They have no food, no water and only the clothes they stand up in.

Twice a year, plastic surgeons, anaesthetists and theatre staff from Britain and Ireland give up their holidays to travel to the Cleft Hospital, the only one of its kind in Pakistan, with Yorkshire-based charity Overseas Plastic Surgery Appeal. 

They dedicate their skills for free, helping children from Pakistan's poorest and most disadvantaged families. Each operation costs around £300 and every penny raised by Ospa funds treatment at the hospital.

Muhammad Riaz, a plastic surgeon based in Hull, is clinical lead for Opsa's surgical team. With expert eyes, he checks Bushra's face. As well as her facial deformity, he also suspects a problem with her vision. Her eyelids are malformed and he notices she had a peculiar way of looking down. 

He'll know more with further examination but, for now, he's sure he can help Bushra and her brother Abdul.

"This girl should have undergone surgery years ago," Mr Riaz said.  "It's not an easy job but we can help her. We can certainly do something to make her life better.

"She should not have had to live like this for so long."

That's how it is for Pakistan's children born with congenital deformities, cleft lips and palates, malformations and growths. In a country where cosanguineous marriages are commonplace, there is almost certainly a link. 

But whatever the reason, Pakistan's children are suffering from an inadequate health care system which cannot cope with demand, consigning those with facial deformities to a lifetime of stigmatisation and ostracisation.

Pakistan has no national health service. For those who can afford to pay, there are first-class medical facilities in major cities like Lahore, Islamabad and Karachi.

The government-run hospitals, charging nominal fees, offer basic facilities, appointments are hard, if not impossible to get, and even when you get seen, patients are often two or three to a bed. They're not an option for those living far away from the major cities.

According to the World Bank, Pakistan spent $6.7bn (£5.4bn) on health care in 2014, $36 for every citizen. By comparison, the UK spent the equivalent of $3,935 on health care for every person in the same year, more than 100 times as much.

The World Health Organisation describes malnutrition as "rampant" in Pakistan, with one in 10 children dead before their fifth birthday. 

Some of the 10,000 born every year with cleft lp and palates and other facial deformities don't even make it that long. Their deformities so severe, they can't feed properly and they die of malnutrition. Special equipment can help feed babies with cleft lips and palates but even the cost of a few rupees is beyond the reach of some.

Cleft conditions occur when the lip and palate fail to fuse properly while the baby is developing in the womb. It's not known why although genetics, malnutrition and environmental factors are thought to play a part. 

It's not that the rates are radically different from those in the UK. It's around one in 600 births in Pakistan and about one in 700 in the UK.

But the difference is, in the UK, children born with cleft conditions undergo surgery before their first birthday. You never see an older child with an unrepaired cleft lip and palate in the UK because they are treated early.

Not so in Pakistan. It's common to see people will into adulthood with unrepaired cleft lips. Their teeth jut out at awkward angles because their teeth buds formed in the wrong place because of the incorrect positioning of palatal shelves. Many have speech problems. 

The Cleft Hospital in Gujrat, opened in 2011, offers hope to people with none thanks to the support of Opsa. The surgeons operate on around 80 children and young people during the week-long "cleft camps", usually in March and October when the ferocity of the climate is more bearable.

Young people like Ahsan Elahi. For 16 years, no-one knew the name of the boy whose teeth jutted out of his gum where his lip should have been. In the small community near Sialkot, they called him "Cursed Face".

The surgeons who saw him at the Cleft Hospital say they had to coax his hands away before they repaired his face and gave him the chance of life.

Now 18, Ahsan is his family's main breadwinner, selling fruit and vegetables from the back of his wooden cart, pulled by a donkey.

"They used to call me “Cursed Face,”’ he said. “Now, they ask me ‘Brother, where has Cursed Face gone? 

"I say I don’t know but I am Ahsan Elahi.  That is my name and that is what everyone calls me now."

“Now, I would like to get married one day.” 

Plastic surgeon Nick Hart founded Opsa 20 years ago. Now retired from surgery, he acts as the charity's ambassador and says it has achieved far beyond what he'd ever imagined with possible.

"When we first went out to Pakistan 20 years ago, we were working in a tiny, hot hospital with an overwhelming number of patients and limited facilities," he said.

Year after year, more surgeons stepped up to offer their services. Wealthy benefactors in Pakistan and other parts of South Asia started supporting the charity's work and it went from strength to strength. They reckon they've helped more than 5,000 children.

But beyond that, it's helped put overseas medical work on an international stage.

"It has encouraged local doctors, nurses and specialists to work in our Cleft Hospital, to gain new skills and extend them into other hospitals," he said.

"It has enabled British doctors, nurses and other specialists to gain experience of working in a more challenging environment.

"And it has put this kind of work on an international stage.

"It shows that if you have a dream, you and your friends can make it come true."

*Visit www.opsacharity.com/donate to support the work of Opsa in Gujrat.