Suz wrote:
We're putting tiles in the bathroom and I want to put border tiles around a
mirror as the main feature. Can a mirror be tiled on? Builder is a bit
wary of this and was talking about screws, but it's slighty ugly. Any I've
seen have rubber washers at the back which means a bit of movement - good
for the safety of the mirror but not great for grouting into the surrounding
tiles.

For sure; I've done it myself.

Attach the mirror first with mirror adhesive (personally I don't think
it's worth not using the real McCoy stuff). You attach a batten to the
wall exactly where you want the mirror, and this supports its weight
until the glue is totally set - you'd want to plan out the exact
position of your tiles in advance to get the effect right.

After the batten is removed, you tile up to the edge of the mirror and
grout in as if it were a big tile.

For best results, IMHO you'd be best off getting a bespoke mirror cut to
size at your local glazier: it's not prohibitively expensive versus the
price of an equivalently-sized off-the shelf item. That way you can
size the mirror to be the exact equivalent of an area of fitted tiles,
so the mirror fits seamlessly into the grid of tiles (unlike the one in
your link!)

David