Blood was pouring from every compartment. We pulled out 270 bodies, pregnant women among them: throats cut, skulls smashed, stomachs ripped open, children with their legs hacked off.

A mile away, Sikh mobs were attacking a Muslim neighbourhood in the narrow streets of the city. On the other side of the new divide between Amritsar and Lahore, Muslim mobs were attacking Sikhs and Hindus. Refugee trains started to arrive from West Punjab after being attacked by Muslims. In Lahore, Sikhs were locked inside a Temple, which was then set on fire. India had gone mad.

This was Independence Day in the Punjab, 15 August 1947. I was staff captain in the Punjab Boundary Force, which was given the task of preserving order. Both the British and Indian armies had been withdrawn from the Punjab, and the Force consisted largely of my own division, 4th Indian.

The Viceroy, Lord Mountbatten, gave it a mandate which guaranteed failure. Just 15,000 officers and troops were supposed to protect an area of 37,000 square miles, with 18,000 villages. He had been warned by Punjab's Governor that at least 60,000 troops would be needed (though with characteristic deviousness, he afterwards denied it).

At least a million people died and 15 million became refugees: columns as long as 25 miles made their way on foot from one side to the other. It was ethnic cleansing on an unbelievable scale. Disastrous floods added to the chaos, followed by inevitable outbreaks of disease.

The refugee trains became the prime target, with trains ambushed at any point during their journey. Railway engineers were bribed or forced to stop at a prescribed spot so that the train could be attacked.

In India, Sikhs moved down the trains, killing every man who was circumcised; in Pakistan, Muslims killed every passenger who was not.

In the countryside, Sikh armed bands or "jathas" roamed from village to village on their murderous mission. Many had served in the Indian Army; they operated with military precision and good radio communication, and left villages filled with corpses.

With air support – which was available – it would have been possible to stem the slaughter, but a veto by Congress and Muslim leaders, endorsed by the Viceroy, banned their use.

The Force was operating under shackles. One of my Gurkha regimental colleagues, a superb officer who had fought with 4th Indian Division through the Western Desert, Italy and Greece, was hacked to death by Sikhs in Amritsar while trying to protect Muslims. Another fellow officer, his face slashed by a sword, was saved by his Gurkha driver.

Mountbatten's quixotic decision to bring forward the date of independence by a year was another guarantee of mayhem, as was his refusal of military reinforcement before partition. The independence date was chosen without clear reason: in fact, Mountbatten boasted: "It came out of the blue. I was determined to show I was master of the whole event." It would seem he probably chose the date because it was the second anniversary of the Japanese surrender: with him it was all PR.

It was soon obvious that he was completely biased in favour of Nehru's Congress Party. He had met Nehru in Singapore at the end of the Second World War and became friendly with him. They both held the same fashionable Socialist views.

The relationship between Nehru and Lady Mountbatten was also a cause of deep concern to the Muslim leaders. Her daughter says: "She was in love with him and he with her, but I don't think it ever became a physical relationship. She had plenty of affairs so there would be no point in lying about it."

Others disagree. But her daughter admits: "The whole family fell under Nehru's spell." A Congress leader said unkindly: "I don't known what he sees in her." But seeing her at close quarters when she came and had lunch with us in Amritsar, it was obvious she was a woman of courage and fierce determination.

Mountbatten's bias certainly affected the partition process. The Boundary Commission was set up under an English lawyer, Sir Cyril Radcliffe, who knew nothing about India and had only arrived six weeks previously. But he was a fair-minded man and did his best to follow the rule that Muslim areas should go to Pakistan.

The Commission was set up to distance the Viceroy from responsibility for the actual boundaries, and Mountbatten was not even supposed to know the decisions. But there was a Congress spy on Radcliffe's staff; he informed Nehru, and therefore Mountbatten, who at once began to interfere.

Nowhere was this more so than in the districts of Ferozepur and Zira. In Zira, 65 per cent were Muslim; in Ferozepur, 66 per cent. Both should have gone to Pakistan. I remember driving up to Ferozepur shortly before independence and everyone assumed they would be part of Pakistan.

But they reckoned without Mountbatten. A telegram came from the Viceroy's Secretary reading "Eliminate Salient", meaning the Sutlej salient where Ferozepur was located. So it was allocated to India, a blow to Pakistan because an important Indian Army arsenal was there, and Pakistan lost most of its weapons. Typically, Mountbatten later said the telegram had been sent without his knowledge.

Mountbatten's behaviour over Kashmir showed the same anti-Pakistan bias.

All in all, partition was a disaster. One reason was that the Muslim League leader, Mohammed Ali Jinnah, died of cancer shortly after independence. He never intended that Pakistan should be a rigidly religious state, but rather a Muslim welfare state. He would not have tolerated a subservient role for women. He secretly liked whisky and smoked heavily (which eventually killed him).

Jinnah never intended that non-Muslims would have no place in Pakistan. The wide white band on Pakistan's flag was to denote the existence of a non-Muslim minority. He said: "We who have complained of discrimination must never discriminate against others."

With Jinnah's death, the dream disappeared. Liaquat Ali Khan, Pakistan's first Prime Minister, whom I had accompanied around the refugee camps (as I had Nehru and Lady Mountbatten) was assassinated.

So we arrive at a Pakistan in which soldiers outnumber doctors nine to one. It is rated the world's most corrupt country. A quarter of its people live in poverty. Only a third can read or write – among the women of Baluchistan, the literacy rate is two per cent.

It was founded on a dream but, 60 years on, there is little to celebrate.