The British thought they would rule India forever; capital was shifted from Calcutta to Delhi

"The Sun never sets on the British empire", went an audacious adage. That is because the British Imperial crown had so many colonies across the world that at any given time, it was day time at least one of the British-ruled lands.

As far as India was concerned, it was called the Jewel in the Crown. But captivity and bondage can never be matters of pride.

India's struggle for freedom notwithstanding, the British were foolish enough to think that they will continue to hold on to power in all their colonies, including India, forever.

The British Royalty liked to exhibit pride in the fact that it presided over such a vast and ancient empire. It even planned and held the Delhi Durbar, also known as the Imperial Durbar, three times: in 1877, 1903, and 1911. The 1911 Durbar was the only one attended by George V.

Plan for Delhi as new capital announced during Delhi Darbar 1911:

The British Emperor made an announcement on 12 December 1911 during the Delhi Darbar. He declared that Delhi was to be the new capital of the Indian region under the crown. This clear declaration of the intention of shifting the capital from Calcutta (now Kolkata) stunned the nation. 

Delhi had been on the subcontinent's trade routes and a coveted seat of governance for several empires that ruled India earlier. The strategic location of Delhi and the weariness that had set in over the rising violence of the nationalists against the British in Bengal made them jump at the ide of developing Delhi for the future. Lord Hardinge also hoped that they could undo the Partition of Bengal and move out.

Accordingly, the foundation stone of Delhi was laid by George V, Emperor of India, and Queen Mary during the Delhi Durbar of 12 December 1911. In a letter sent from Shimla to London, dated 25 August 1911, Lord Hardinge – the Viceroy of India – elaborated on the need to move the capital. That angered Lord Curzon, the previous Viceroy who had ensured that the Prince of Wales laid the foundation in 1905 for Queen Victoria's memorial (as she had died in 1901). 

Work on new capital hit by the World War:

Work began on the new capital in Delhi. British architects, Sir Edwin Lutyens and Sir Herbert Baker were assigned the work. They chose the southern plains beyond the old walled city of Shahajanabad as their site. In sharp contrast to the old walled city, the new capital's roads were to be huge and broad.

The area was first made a district province of Punjab. Lord Hardinge hoped that “New Delhi” would be ready within four years. But suddenly the World War was upon Britain. WWI took up precious funds. With coffers dry, it took 20 plus years to finish work on what came to be called “New Delhi” (in 1927).

By the time the British could formally inaugurate the new capital in New Delhi, it was 1931. Delhi was inaugurated as the capital of British India by Viceroy and Governor-General of India, Lord Irwin, on 13 February 1931. 

They barely ruled a decade from here, that WWII struck.

The Second World War had them bargaining with Indian leaders for support against Germany's advances. 

And the British wanted out:

As things eventually turned out, representatives of the British colonisers had to sit across the table and negotiate their exit in early 1947. On 15 August 1947, India was free. 

As the world and his fellow countrymen watched in pride, Nehru has his iconic Tryst With Destiny speech. After finishing his speech when he walked out of the assembly hall, thousands of people rushed forward to embrace him and the other leaders. Watching them, Nehru said to one of his aide standing beside him, “You know, exactly ten years ago, in London, I had a fight with Linlithgow, the Viceroy. I got so mad I shouted, "I'll be damned if we don't have our independence in ten years". To which the Viceroy said, "Oh no, you won't, because India will not be free in my time Mr Nehru, nor in yours either".

The Sun had set on the British empire.