An estimated half a million South Sudanese remain in the Republic of Sudan - formerly the northern part of Sudan before the country split in two in July 2011. Many took refuge there as displaced people from the civil war, which began in 1995, continued intermittently and which was fought mainly in the South.

Consequently, they lived most of their lives knowing next to nothing about where they came from. The majority no longer own any possessions in the South, such as plots of land on which to build houses. There are also those who were born in the North. They are strangers in the place they call their homeland. They cannot even really be called returnees.

The common denominator among them, however, is their joy at returning to an independent South Sudan, despite facing monumental challenges and difficulties on their way. When asked how they feel about returning home after so many years in the North, several told me: 'I am happy to be back to my country, even if I have to drink a glass of water for dinner!'

I heard the same response at Juba port, where hundreds wait in transit before heading to Juba town, and at the way station, where people wait for their luggage, transport and health checks before undertaking the final leg of their long journey home.

Most refugees, displaced people or even people who migrated voluntarily to other countries, tend to have fond memories of their homeland. But among the South Sudanese returnees, the feeling is so strong that it verges on passion. Even those who were born in the North seem to share the same level of sentiment. I wanted to know why.

I went to meet three elderly people who had arrived from Khartoum recently and a young woman who was born in the North. I asked them individually to tell me why was it that they had decided to return to the South.

The reasons they gave were astonishingly similar. Joseph Lino says that he is 67, but looks much older. He has spent most of his life in a displacement camp in Khartoum. 'Life for a Southerner in the North is full of misery. We were treated as if we were foreigners in our own country. The conditions we lived and worked under were those of second class citizens,' he said sadly.

Joseph told me that as a Southerner, there were only a handful of jobs that he could do, such as carpentry, building, working as a cook or other menial work. Very few Southerners were taken into the civil service, even after the signing of the Comprehensive Peace Agreement in 2005, which stipulated that 20% of the civil service posts should be filled by people from the South. The best a Southerner could aspire to, he said, was to be drafted into the army or in rare cases, the police force.

'This is why many educated young people from the South, had no option but to leave the country and seek opportunities abroad,' he added.

For Marino Wani, a 68 year-old former military police officer, who worked in the force for 17 years until he resigned from his position, the sheer discrimination at work, particularly with regards to promotion, made him realise that there was no future for him in the force.

'For all those years, I remained in the same grade as the day I joined the force,' he said. During that time, he added, he trained many officers of Northern ethnicity, who went on to become his bosses.

Viola Joseph is a 30 year-old mother. She was born in Khartoum and has never visited or lived in the South, but decided to come to live in the land of her ancestors. She said that though she had not lived anywhere else to make a comparison, she felt that her life in the North was not normal.

'We lived within our own society. There has been no natural mixing of the Southerners with the Northerners,' she explained.

Viola worked with a theatre troupe. She says, the only place Northerners and Southerners can intermingle is in the work place.

Viola insisted that on personal level the treatment of the majority of Northerners was good, particularly before the referendum. Viola lost her job after working for a year and had to resort to one of the few jobs that Southern women can do to feed their children: brewing local beer. She said the practice is strictly forbidden under Islamic laws observed in the North and can attract severe punishment if discovered, including public flogging.

She said according to reports she read, there are currently some 3,000 women of Southern origins languishing in the northern prisons for brewing beer, even after independence and the call for Southerners to return to their country. Viola explained that Southern women were forced to do it because it was the only source of income with which to feed their families and to pay for school fees.

'We did not do it out of choice. You would be insane to do so, considering the punishment,' she said.

Peter Samwel, who is over 70 years old, went to the North in 1964 to live with his uncle, who worked as a carpenter all his life. He said, life in the North became untenable after the referendum of January 2011, in which an overwhelming majority of South Sudanese voted in favour of secession.

'Since then, the already existing fault-lines in North-South relations became ever more pronounced. Northerners could say and do openly what in the past was hidden behind a veneer of hypocrisy,' he said, clutching his walking stick as if to emphasize his point.

'Many Southerners were summarily laid off from their jobs; others were asked to vacate their rented properties; children were stopped from continuing with their education and I have reports that even some were refused treatment in hospitals. What is going on is unimaginable, but nothing is reported,' he said.

Peter ended his conversation with me by asking me to write about this so that, in his words, 'they quickly bring our remaining people home before disaster strikes when the deadline expires in April.' I was taken aback by what he said and asked him what kind of disaster could possibly happen when the 8th April deadline set by the Sudanese government for Southerners to leave the North and return to South. Peter's reply was short:

'Perhaps you didn't hear about what happened to the Southerners in Khartoum in the aftermath of the death of Dr (John) Garang in 2005,' he said, standing up, reaching for his walking stick and furiously striding away.

I had, in fact, heard. When news of the death of Dr John Garang - the leader of Southern SPLA rebels who signed Peace Agreement and became part of the government of unity – spread in July 2005, Southerners rioted in the capital Khartoum, burning cars and buildings. In retaliation Northerners attacked Southerners in the streets, killing an unknown number of people.