Any suggestions how to prevent this?

The strawberries are already lifted up on straw, and don't have a slug
problem, but the ants get there before I do, and fill the strawberries with
tiny tunnels as soon as the berries start to turn red.

As ants can climb, I am not sure that lifting the strawberries further off
the ground will help.

Incidentally, last year I posted about my strawberry 'Temptation' plants,
which were producing tiny alpine-like berries. This year, they are doing
exactly the same, but the other varieties planted in the same place this
year have decent sized berries, (but for the ants).

I conclude that they were not 'Temptation' at all, but some sort of alpine.
Next time I'll buy strawberry plants from a fruit specialist, not a
supermarket :-( .

Victoria