They knew no such thing because it didn’t happen, and it probably would not have happened until very much later.
Mr Bury cites the example of India, which did not gain independence until 1947, and it seems reasonable to suggest that Britain’s experience in a much smaller and closer colony, Ireland, made things a great deal easier for Gandhi and his followers almost 30 years later. Home Rule was an issue in Ireland since at least 1870, when the Home Rule Association was established, but its achievement was regularly thwarted by the Conservative majority in the House of Lords.
The outcome of the 1918 general election was as close to a referendum as Ireland could get on that subject at the time and the result showed no sign of changing attitudes in Britain. Furthermore, the delay of almost 50 years made Home Rule an inadequate option - events had moved well beyond that.
The proper time to have a centenary celebration would be in 2022, which would mark a success, rather than in 2016, which would mark a failure. Surely it is time to accept the fact that this State came into existence following a period of armed conflict and that those who choose to live here are effectively legitimising what happened during that conflict.
Neither colonialism nor the manner of its overthrow could be regarded as constitutional, but the constitutional option has got to have the greater level of moral justification.