A friend told me that EY BAS are letting small numbers of people go, as business has been very slow for them recently.It's all been very quietly done, in order not to alarm staff.Is there any truth in this?

I would not be surprised. A number of teams haven't had a piece of work in months and others which were launched last year (e.g. Strategy) have not won anything so far. There are a lot of people who are filling in on projects outside their designated group, or who are on transfer to risk, audit, etc. They are likely to moved on or asked to re-apply to jobs in those groups. That said, other teams (e.g. in IT PM) are still busy enough.

A colleague of mine just transferred internally to BAS a couple of weeks ago, so can't be across the board.