Seven decades ago, at the stroke of midnight on August 15, 1947, India and Pakistan gained independence, but at a terrible price.

The breaking up of British India into two independent nations – Hindu majority India and mainly Muslim Pakistan – provoked one of the most terrible catastrophes of a turbulent century.

About a million people – no one knows the number for sure – were slaughtered as Hindus and Sikhs on one side and Muslims on the other embarked on a swathe of violence. Twelve million people became refugees, many traipsing across the new international borders in seeming endless columns.

It wasn’t supposed to be this way.

A radical Labour government was elected in Britain at the close of the Second World War, determined to grant independence to our biggest colony, India. The dashing Lord Louis Mountbatten – uncle of the Duke of Edinburgh and distant relative of the Queen – was given the role of the last Viceroy of India. His task: To organise an orderly British exit and a seamless transfer of power.

Mountbatten was a naval officer who had served as the Supreme Allied Commander, South East Asia. As befits a military man, he wanted the job done quickly. And India paid the price.

India’s main political leaders – Mahatma Gandhi, Jawaharlal Nehru and Muhammad Ali Jinnah – couldn’t agree on what should follow British imperial rule. Jinnah, the founding father of Pakistan, argued that British India’s Muslim minority – about a quarter of the total population – were a nation in their own right. Nehru, independent India’s first prime minister, reluctantly agreed to the dividing of the country.

That meant dissecting two of India’s biggest provinces, Punjab and Bengal. A task that should have taken months, perhaps years, was completed in five weeks by a British lawyer, Cyril Radcliffe, who had never been to India before. And never went back.

He had to carve up India based on unreliable census returns and out-of-date maps. The news of where the new boundary would run was announced on August 17, just two days after independence.

(Image: Getty)

Clashes between different religious communities intensified in the run-up to independence. It wasn’t simply spontaneous mob violence. Local politicians and gang leaders were involved, and, in the aftermath of a world war in which millions of Indians fought, there were a lot of men around with military training and army-issue weapons.

The violence spiralled out of control. Trainloads of refugees were massacred. Tens of thousand of women were abducted and raped, and then either killed or married off. Each mass slaughter prompted demands for revenge and neither the politicians nor the police were able to stop the frenzy.

The steps taken to enforce law and order and deal with large numbers of refugees proved to be utterly inadequate. It was an inglorious end to imperial rule in India.

In Punjab in particular, Hindus, Muslims and Sikhs had lived together peaceably for generations.

No one expected a forced mass migration. But by the close of 1947, almost all Hindus and Sikhs in west Punjab had fled east, often encountering long processions of Muslim refugees heading in the opposite direction.

(Image: Reuters)

It was one of the biggest population movements of the modern world and a grim start to nationhood.

But within weeks, events took a turn for the worse. Britain had pulled out of the “jewel in the crown” of its empire without a final decision on who should rule the mountain kingdom of Kashmir in northern India. The maharajah, or ruler, was a Hindu. Most of his citizens were Muslims. Both India and Pakistan claimed the princely state.

By the end of October 1947, India and Pakistan were fighting over Kashmir. The conflict remains unresolved. Many Kashmiris would prefer independence.

India and Pakistan have a lot in common. They share a passion for cricket. If you speak Hindi, India’s main language, then you will understand Urdu, Pakistan’s official language. India’s Bollywood movies are big in Pakistan. Pakistani TV soaps are avidly watched in India. But the two nations have never become friends.

(Image: Getty)

There are no direct flights between the two capitals, and India has more trade with Belgium than with Pakistan. The land that was allocated to the new Muslim nation was divided by a thousand miles of Indian territory.

In 1971, with the support of the Indian army, East Pakistan broke away to become the independent nation of Bangladesh. For many in Pakistan, it felt like a second partition.

The intense rivalry with India has destabilised Pakistan’s democracy. The army is by far the most powerful institution. And radical Islam has been able to use the war cry of saving Muslim Kashmir from Hindu India to win recruits and money. Meanwhile, India has developed into a major world power, with a robust – if flawed – democracy and a booming economy. Muslims currently account for one-in-six of India’s population, but it is forecast that it will soon be home to more Muslims than any other country.

(Image: Getty)

Britain’s imperial history in South Asia explains the large number of migrants who came here to find work or be educated. There are almost 1.5 million people of Indian descent in Britain and slightly more whose forebears are Pakistani or Bangladeshi.

The tensions between different religious groups that flared up 70 years ago have inevitably had an impact on the outlook of migrants in Britain.

But as British Asians of all communities reflect on the immense tragedy that accompanied independence, they do so more in sadness than in anger.

Gurinder Chadha: Director of bend It Like Beckham

Gurinder Chadha’s parents were born in modern-day Pakistan before fleeing to India amid the violence of Partition.

Her paternal grandfather – a Sikh - was working in Kenya at the time, leaving her grandmother to care for their five children.

Gurinder said: “My Mum always said where she grew up in Rawalpindi, she had friends who were Christian, Muslim and Hindu.

“But as Partition approached, she said it was like somebody put black magic in the water. Everything changed, everyone went from living happily to fighting each other.”

As attacks on Sikh and Hindu families increased, they fled their home with nothing more than the clothes on their backs.

Gurinder, 57, said: “Their youngest daughter was still breastfeeding, but after three days on the train, my grandmother’s milk dried up. The baby starved to death.”

When Gurinder’s grandfather returned home to find the family gone, he spent 18 months searching refugee camps.

Eventually he arrived at a camp in Puniput, north of Delhi, and spotted a boy he recognised.

Gurinder said: “The little boy led him through the camp to his family – and they were reunited.”

* Dr Andrew Whitehead is a historian and the former head of BBC World Service News

Saira Khan: Loose Women Presenter

(Image: ITV )

Saira Khan returned to Pakistan, where her Muslim parents were born, for a TV show 10 years ago.

Saira’s dad, Jan Mohammed Khan, and mum, Hanifa, were among those who fled their native Kashmir.

Saira said: “When my parents came over to England, they thought it was only temporary. They thought they would make some money and then they would go home. But of course they never did.”

Her childhood was vastly different in Britain.

She recalled: “Mum and dad came from Kashmir. They left all their family behind, they couldn’t really speak the language and they had four kids pretty quickly.

“I was happy as my mum and dad were always there, but it wasn’t a smiley upbringing.”

Saira, now 47, went to visit Dathot, her father’s ancestral village in Pakistan.

“When we were all grown-up, dad and mum went to Pakistan to see their family,” Saira said. “He had not been back in 30 years.”

She added: “All the time I was growing up, my dad would tell us about Pakistan. It was like some kind of fairy tale, with mountains and jungles and cobras.”

“It really was like something out of The Jungle Book.”