There is a
web bolt on for £7.50 a month.
However when reading their T&C's earlier this evening I saw that it said you had to be on specific tariffs in order to get a bolt on:
Taken from
Bolt on T&C's
"1. Bolt Ons are available on Pay & Go Original, Pay & Go Talkalotmore, Favourite Place, O2 Trio and Pay & Go Talkalot tariffs."
EDIT: I have just found in the terms and conditions:
If you have a Browsing or O2 Web Bolt On, your Text Anytime inclusive browsing allowance will be used first followed by your Bolt On allowance. so you must be able to get the web bolt on for the online tariffs too
