From Pete's site:

Those of you that have been following the current case involving Pete will
be aware he had stated that he had been in contact with the Internet Watch
Foundation (IWF) regarding his concerns over child pornography on the
Internet. At the time the story first broke the IWF denied that they had in
fact heard from Pete. They have now admitted that they did in fact have
communication with Pete on a number of occasions. 
This is the remit of the IWF (taken from their website http://www.iwf.org.uk
)
'The Internet Watch Foundation works in partnership with ISPs, Telcos,
Mobile Operators, Software Providers, Police and Government, to minimise the
availability of illegal Internet content particularly child abuse images.
Our Internet Hotline can deal with reports of potentially illegal Internet
content, such as websites, newsgroups and online groups that:
Contain images of child abuse, anywhere in the world.
Contain adult material that potentially breaches the Obscene Publications
Act in the UK.
Contain criminally racist material in the UK.' 
As you can see the IWF was the correct body for Pete to approach but since
some of the media have reported the fact that the IWF denied receiving any
communication from him we thought it was important that this updated
information was published.
In response to this information Pete has said :
"You may recall that among the media frenzy of a couple of weeks ago,
representatives of the Internet Watch Foundation told the press and the news
stations that they had never heard from me. I, of course, know that I did
communicate with them several times last year and they have now supplied to
us copies of my e-mails to them, one in August and the rest in November. My
lawyers have written to the Founder of the IWF, Mark Stephens, who was
adamant that they had never heard from me, asking for an explanation."