Adblock Plus has been efficiently blocking advertisements for me in Iceweasel (Firefox). But it was today that I noticed that the ABP icon was green while reading news items on BBC. It wasn't blocking the advertisements on BBC pages. On further checking I found out that ABP has whitelisted BBC! That is what was causing the adverts to appear.
A simple disabling of the whitelist entry for bbc returned the page to its clean form. What would we do without ABP?
Update: As Wladimir pointed out, the filter list was automatically updated to solve the above quirk. So if you happen to see those adverts, update your filter.