A very common scam, I've had loads of these calls over the years. Usually a scouse woman. They claim to publish booklets etc to the emergency services, or charity or say they're from the Police usually.
When I had my valeting business I used to get one a day most days, they target mobiles also most of the time as they know they stand a good chance of getting a person and not a receptionist.
NEVER say yes to anything, they record the call and I've read loads of posts from people who get an invoice some time down the line for an advert "here's the invoice to the ad you agreed to" sort of thing, then they threaten you with court etc if you dispute it. Very nasty operators, just put the phone down straight away !