Abolition in Britain was promoted as a moral mission, but maybe this wasn't true.What does Britain gain promoting it as a means of promoting humanity?
The case for abolition in Europe was seen by most as a moral mission, but there is evidence that this wasn't the case. So, what would Britain gain by promoting it as something so humanitarian?
I do not agree with the basic premise of the question, which is that Britain would have actually had ulterior motives for abolition and that it falsely portrayed abolition as a moral crusade. I would argue that the British economy was in fact harmed by the abolition of the slave trade. This would seem to imply that Britain must have been acting on moral grounds because it was not helping itself economically.
However, there are those who have argued that Britain pushed for the abolition of slavery and the slave trade because it was no longer useful to them. In this view, the rise in British capitalism was making slavery economically obsolete. Getting rid of slavery, then, would actually have helped the British economy and British capitalists in particular. The British claimed that they were acting on moral grounds so as to look good in the eyes of the public and of the international community even though their real motive was to do what was best for the capitalists.