There have been no such cuts. This is a frequently made claim but it isn't true.
Here's a graph of the budget of the Department of Health:
https://ichef.bbci.co.uk/news/624/cpsprodpb/BA1A/production/...
As you can see it only ever goes up. This is in "real terms" i.e. with inflation taken into account.
Usually activists who make this claim and are put under a bit of questioning pressure will admit that by "cut" they mean the budget was increased less fast than they believe necessary, which isn't the same thing.