I too just received the 'Hi, this is John from the Information Team' message. The call was left by 0871 240 9000 and asked me to phone back 0871 240 9911. Scam alarm bells went off in my head soon after listening to it, since there was no mention of a company name or any indication that he knew my name.
Reported to Ofcom this evening via their website -
http://www.ofcom.org.uk/complain/landline/nuisance/silent/?itemid=284827 - took me a while to find this form! I recommend reporting it if you've received one of these messages as action is only taken if Ofcom receive some (unknown) number of complaints.
Could this website have a category for suspected scam numbers? I would have liked to find something other than 'number not found' when I searched, and it might just help others avoid calling out of curiosity.