I went to see the movie 1917 last week. There were several trench scenes where blacks were serving in the trenches with the main characters' battalion and there was a scene on a truck where there is Sikh soldier who was a member of another British battalion.
I know that a large number of Indians, West Indians, and Africans served with the British Army in Europe during World War I. My understanding is however that they were not in the regular British infantry regiments, but served in either infantry and cavalry regiments in the Indian Army or in the case of the blacks were in their own units, usually in service / support units.
Is this true? If so, when did the British Army started integrating their regiments? Post World War II?
There was Lieutenant Daniel Tull who served in the Middlesex Regiment in the Footballers Battalion, but was he an exception?
https://en.wikipedia.org/wiki/Walter_Tull
I read recently that Lord Milner refused to train U.S. "colored troops" during WWI, even though he felt U.S. troops would be able to be deployed faster if trained by the British.
Yet again I am very late to this debate, but do have something to contribute I think. I have in my possession a photo of a company of the 1/4th Gloucesters, fresh from the Somme and dated July 1916. Each member of the company carries a memento taken from the German trenches, and while most faces are of your typical English Tommie, there is one fellow with a black complexion who is clearly of African descent.
I have also come across a fellow who was born in Colombo, Ceylon (as was) and who enlisted in 1790 in the 52nd Foot at Negapatam, India. His physical description suggests to me that he could have been of mixed race, although no-where does it explicitly state that of course. He was still serving in 1808, so was one of the first men to be trained in light infantry tactics at Shorncliffe.
We'll never know what racial attitudes these men faced, but they clearly stood shoulder to shoulder in the ranks with their comrades.
"All commanding officers in the BWIR were white, and no black man was permitted to hold a higher rank than Sergeant. Once deployed, all fighting was carried out by white soldiers, while the BWIR were given support work loading ammunition, laying cables and digging trenches. Most were unarmed."
https://retronaut.com/content/1914-1918-black-british-forces-of-wwi
See also
https://www.dailymail.co.uk/news/article-7911347/Soldiers-Empire-DID-fight-regiments-British-WWI.html
As far as I know, the British Army never operated segregation as such on an individual level, so never really integrated. In our period the British regular regiments recruited locally, so reflected the make up of the volunteers to the recruiting party. In the latter part of the period, recruits were often drawn from the militia, so even more likely to be localised. Attestation documents don't record race, but do mention complexion. However, it would be quite dangerous to assume that 'dark' was synonymous with ethnicity.
Likewise names were anglicized, even by Germans. As a result the ethnic diversity of a regular regiment is difficult to establish. Undoubtedly this has meant that the contribution of black soldiers has gone unnoticed.
The poor health reputation of foreign stations led to the practical establishment of dedicated colonial regiments. Natives of those climes were seen as more resistant to the depredations of disease. The Indian Army was the responsibility of the EIC, and for political and religious reasons largely followed the fracture lines of the sub-continent.
This is not to deny the prejudicial and racial attitudes in our period, which today we would find deplorable. However, discrimination and bigotry wasn't restricted to race, but included class and religion. Emancipation of the Catholics and the opening up of commissions had to wait to 1828 for example. "Our Willie", Field Marshal Sir William Robertson Bt GCB GCMG GCVO DSO going from Private to Field Marshall was over a hundred years in the future.