I can answer your question with respect to British rule in India-Pakistan-Bangladesh.

Firstly the British rule did not fall in one day, it was weakened through multiple waves of protest spread over a century, some of it was peaceful some not so.

The Revolt of 1857 is considered to be the first major war for independence. The whole of India was put under martial law and power to punish was given even to ordinary Britons. The only form of punishment was death. Mutineers were hung and blown from cannons. In Oudh alone, 150,000 were killed. Reinforcement had to be brought from Britain and their authority was re-established only by 1859. The British were successful in winning the "bloody war".

Despite a few exceptions the challenge to colonial rule was essentially peaceful.

The "moderates" agitated within the walls of law.

Even the "extremists" were limited to passive resistance- boycott of government institutions and foreign goods.

Proportional to the form of protest, government repression was mild- rebel leaders were arrested and deported. However this was not always the case. In 1919 Amritsar, British troops open fired at a crowd peacefully protesting the arrest and deportation of two national leaders, killing about 1000.

There were certain radical revolutionary groups but they did not consider violent mass revolution practical. They performed individual heroic acts such as dacoities, conspiracies to get help from the enemies of the British, and assassinating unpopular British officials. One of these groups was the Gadhar party, who in 1915 planned an armed revolt in 3 town of western India. This was foiled at the last minute and 45 people were hanged.

Towards the last decades of British rule (from 1915 when Gandhi returned to India), Gandhi was at the forefront of mass agitation and was responsible for keeping it peaceful. At any instance of violence he withdrew the movement. Non violent movements such as non cooperation, civil disobedience and mass strikes were organised.

With a few exceptions, the movement for independence was non-violent and bloodless.

Another reason for peaceful withdrawl of British rule was the factors shaped by the WW 2. UK was no longer a global power, British soldiers were tired and their economy shattered, there was an anti imperialist wave throughout Asia, and the Labour government which came to power in 1945 was sympathetic to India.

I hope that's helpful.

First up, I'd consider the end of the British Empire a relatively controversial subject. Not because there's a raging debate about it among the UK public, but rather because there's not.

As British people we've relatively benign view of Empire, but one that's I'm afraid not entirely based on reality.

There are a wealth of reasons why the Empire went when it did, why it happened so quickly and how it happened. However I'd seriously challenge the idea that it was totally bloodless or peaceful.

Rather I'd suggest that after initial resistance and tough lessons learnt about Britain's new post war role in the world a combination of war weariness public antipathy and economic pressures, through debts and the end of trade dominance, led success politicians and leaders to see the Empire as no longer sustainable.

But I don't think it was bloodless.

For example the Mau Mau rebellion, or Kenyan Emergency was certainly not peaceful. It lasted 4 years, or over 8 depending on what you count, and cost the lives of between 12,000 and 20,000 people.

Equally the uprising in Malaysia caused a similar level of death over an even longer period.

However if you want to understand the full awful impact of British decolonisation then you probably want to look at India.

We may well have not fought a war to retain India (instead acquiescing to independence after a long and largely peaceful campaign of resistance) but in partition we planted the seeds for the country (or countries at partition) to under go bloody massacres, massive movements of people and death and poverty as a result. It's estimated that between 1-2 million people died because of partition with 14 million becoming refugees. All because of British policy.

This has led to years of conflict and division in the sub-continent that still has ramifications today. It definitely wasn't peaceful.

Equally our the end of our mandate in Palestine was a period rocked by civil war and strife, with small casualties for the British, set against large losses for competing nationalist groups.

Interestingly both of these last instances have two stark similarities. 1) educated and motivated nationalist independence movements 2) a war weary British public, Government and army unwilling to pay the price to hold on to Imperial possessions.

This pattern was repeated around the Empire as independence movements, buoyed and inspired by the example of Ghandi in India, or Aung San in Burma to negotiate an exit of the British agitated for independence themselves.

Add to points 1 & 2 the massive debt the U.K. held after World War II, the crippling impact of the war on infrastructure in the UK and the insistence of the USA that, if it was to lend us money and support in WWII (see the Atlantic Charter) and afterward in our reconstruct, we open our colonies to trade and support self determination while also allowing sterling to be freely traded. This resulted in a seismic shift in the power position of the U.K. To put it bluntly the British were bankrupt, they'd won the war but lost their power, economic strength and prestige in the peace.

So though the end of Empire wasn't as bloodless (India, Kenya & Malaysia alongside others) as people often like to think it was, it did happen a lot quicker and with less resistance from the British than other Empires.

The perfect storm of pressures upon the British state and people, led to an inability and lack of desire to hold onto its Empire. Politically and emotionally but also importantly in the resources necessary to do so.

One finally note. The British Empire, outside of predominantly ethnically Eurocentric holdings (Australia, New Zealand, Canada etc) if it was anything was an empire of trade and resources held together by a few Europeans and people of mixed heritage ruling much larger indigenous populations. Once nationalist movements started to grow and gain a voice and be inspired by each other, and through the shrinking of the world (though easier communication such as newspaper, radio and books) started to talk to each other, the writing was on the wall.

After the huge blows dealt to British economic, military and cultural power by WWII and the settlement afterwards many came to believe that to hold on to the Empire was futile.

And just to throw one last car amongst the pigeons, combine this with a working class Labour Party and sometime Government instinctively anti-Imperial taking a new role in British politics and a very real threat of a new war with the Soviet Union and retaining Empire all of a sudden seemed a much lower priority.

Was it peaceful?

I've always thought about the British leaving India and Palestine as resulting in bloodbaths and conflicts which have killed and displaced millions and continue to this day.... Not to mention all the places I have no knowledge about (Burma/Kenya etc).

It's worth mentioning that much of French decolonization wasn't all that bloody, too. Algeria and Indochina really stand out and we hear about them because of the proximity of one to Europe (as part of metropolitan France, legally) and the US engagement with the other as part of the Cold War. But the independence of Africa otherwise was relatively peaceful in conflict terms, with all the vitriol and energy happening in ideas and politics. Similarly, a lot of the French Pacific (where it decolonized) was pretty easy. French Somaliland had to be staged away to become Djibouti, because they kept voting to remain tied to France, and many other islands and small holdings--the French equivalent to Britain's 'resort empire'--have remained French, with varying degrees of integrality to the order in Paris. So I think it really is a lot of perception with the Anglo-French comparison, as others have noted with the Kenya Emergency, the Malaysian case, various moments of crackdown on protests such as the 1947 shootings in Ghana (Gold Coast), the ongoing messes created in South Asia over centuries, and other shorter-burning examples like the Palestine Mandate. The only modern decolonization that I would characterize as eminently violent is Portugal's, which is the result of the Estado Novo and its philosophy towards colonies and the weird concept of Luso-Tropicalism that only truly collapsed when Lisbon did in 1974's Carnation Revolution. Spain's, of course, is mostly much earlier, and I don't tend to put it in a comparable frame because I'm an Africanist. Spain's serious colonial holdings, when relinquished peacefully, had preconditions for disaster firmly in place (e.g., Macias Nguema in Equatorial Guinea), and of course they still have two colonies in effect on the coast of Morocco. The Spanish Sahara case is also interesting but I don't know enough about it to really unpack the players.

Fred Cooper's Africa Since 1940 is a useful discussion of the African cases; I believe it's out in a new edition, although I still refer to the first. Both Dane Kennedy and Jürgen Osterhammel with Jan Jansen have 'short history' volumes on decolonization out dated within the last two years, and each author (or pair of authors) focuses on different elements of the process. I'm still waiting for my copy of Dane's book, or I'd be drawing on it.

To call it "bloodless" and focus on the political/diplomatic aspects leaves out a few key factors. For one, the nature of the domestic revolutionary movement (ie whether primarily militant or political). For another, the capacity of either side to engage in an armed campaign of the scale needed to over power the opposing faction. Thirdly, the likely costs of that armed struggle compared against the benefits of winning.

Compare and contrast the UK's response to independence movements after the first world war vs those that arose after the second.

Ireland fought a bloody war of independence in 1920 and though it gained self rule, it was still forced by the UK to remain nominally a Dominion within the Empire. Its declaration of full independence on the late 40s merited comparatively little attention.

In 1919, a nonviolent movement began to demonstrate for Indian independence and faced brutal repression from British forces (eg Amritsar massacre).

A generation later, in the wake of WWII, Britain's ability to maintain an overseas empire from its significantly weakened position coincided with a renewed push for full independence. The consequences of losing India were obviously far greater than those of losing Ireland, but still did not justify the human cost of embarking on a war of subjugation.