First, little of this is UK-specific, the rules for what should go on the ATIS come from ICAO.
Second, the info is there to assist planning and briefing for the approach. One airport I worked at took the sensible decision not just to include the type of approach but how the pilot can expect to get there - normally "Expect radar vectors to the ILS", but sometimes it had to be "Expect vectors to a visual approach" or "Expect procedural ILS approach depending on serviceability of equipment and so on. As has been pointed out, just because there is an ILS doesn't mean it can be used - I'm sure that knowing this can help planning as opposed to assuming.
Originally Posted by billyt
I always have assumed that the statement "expect an ILS approach" indicates that a visual approach is unlikely due weather conditions.
Not something to be relied upon.
Sadly, although NOTAMs are a pretty good idea, many pilots just don't seem to read them or have the foolish idea to take-off before something happens/fails and a NOTAM can be sent. ATC is there, in part, to provide information to help the pilot conduct the flight safely - the general point is that it's better to have something passed to you unnecessarily than not be told something that you need to know.
Originally Posted by Uplinker
As I say, this particular point might seem petty, but it is one of a number of apparently (to me) uneccessary things that have appeared over the years, and I want to understand the reasons for them.
Another 'sadly'. Many of the things that are done that appear to be obvious or make you think 'Why are they telling me not to do that, no-one would do that?' are done because someone has been stupid enough to try it. And why do we now have a backside-covering culture? It's because when someone has done something stupid, the first thing they do is look for someone else to blame!