Oops, it's better to use \Z than that final (\s|$) I had suggested (see post above).

The MkII Match valid IPv4 at start of line (drum-roll please):

/^((\d{1,2}|1\d{2}|2[0-4]\d|25[0-5])\.){3}\2\Z/

LaurenceHunter => "Life is loud, life is 60p/min."