There is nothing to stop a company using LIFO. However most don't use it as they tend to want to get rid of the longer term staff who tend to be more highly paid. Its not illegal though
Yes I agree with that sentiment, I'm hearing from my previously boastful wealthy friends that in the SME sector the highly paid "office manager" type is suffering, not quite being pushed "out" but having hours reduced to a 3 days week
LIFO is definitely not illegal. The reason it was always popular is that the criteria for choosing people for redundancy is supposed to fair, and not based on personal issues.
If you have 6 people doing the same job and you need to let 3 go, it is hard to choose the 3 without being seen to target individuals and lay yourself open to an unfair dismissal claim, so LIFO might be the fairest way to decide.