Using regular expression in query

[Gandalf]

Hi all,

I need to filter out rows like 'A <number>'
where the second character=space character.

To start with I have the expression: ~* '^A' which will
filter out any row starting with 'A'.
Now there must be something to indicate the space character.
(in Perl '\s' defines <space> but not in Postgres it seems)

Grateful for any help on this!