Comfort
Actually, the US beat The Hun twice, and the Soviet Union beat them once. And while Britain was busy defeating The Hun the second time around, the US beat the British Empire, fulfilling FDR's dearest wish.
We even got rid of that Empire of ours (eventually). So our 20th century history is only about a million times better than that of most of our EU neighbours.
The 20th Century history of Britain is only an improvement over the previous several and comparable to the imperial history of other states if you turn a blind eye to events prior to 1925ish in Ireland, the Boer War, events up to 1947 in Palestine/Israel, events associated with the Indian Empire including the gross mismanagement of the independence and partition of India and Pakistan that resulted in millions displaced and dead, the conduct of Britain in Africa as African states fought for independence, support of the moral cesspit that was Apartheid South Africa, and the entire progress of a thirty odd year period of hell in Northern Ireland that was preceded by the turning of a blind eye to decades of a form of apartheid within Northern Ireland that resulted in Civil Rights marches in the province in the late 60s, part of a campaign for civil rights that was necessary because almost half of the population had been systematically denied civil rights since the 1920s. This was within the United Kingdom.
Britain didn't 'get rid of' its Empire. The Empire was taken back by its rightful owners.
You really should not rely on Ladybird books for your historical knowledge.
BigChoc
In NI, over-agressive tactics didn't beat the IRA into submission; they massively increased IRA support and escalated the conflict:
Yes indeed, and if successive governments had gone further they might have beaten the Provos into submission. As things stood, they did what the British always did as soon as they encountered serious opposition to colonial rule (i.e. during the entire 20th century); they fought but only up to a point and therefore lost. The lesson of the previous war in Ireland was not lost on the Provos - escalate and the British will come to the table. The very existence of NI came about due to Britain's refusal to stand up to threats made by the Unionist lobby, prominent among which were high ranking army officers and members of the Tory establishment. Take a look at the Curragh Mutiny if you want an example of Britain bumbling through politics and war, accommodating behaviour that came very close to treason on the part of high ranking officers instead of doing what was necessary and salutary. This sorry episode was very instructive for everyone except Britain.
The lesson Russia is teaching ISIS and any group with its sights on Russia right now is 'we will not back down and we will do whatever is necessary to win'. And this is a reasonable message to send to terrorists, because the alternative is to let them have their way, conquer enormous territories, commit genocide, ruin everything in their path, and threaten all of their neighbours. It has to be one winner or the other in the war against ISIS. There is no middle ground.
Slippery - wrt what you call demonising their elected government - is that not a big part of enjoying life in a political entity that is 'as free as it gets', or something like that...