In the UK, is it illegal for an adult to go out into the street and take photos of young teenage boys with out them knowing.?

As long as it's LEGAL to photograph in public where there is no expectancy of privacy, even though it may raise suspicions where there may be no cause for suspicion... the "malice" may actually lie in the minds of those with malice in their minds. In fact, if photography in public is legal and there is no expectancy of privacy, the person can photography anyone in public without permission... what can any law enforcement agent(s) do? NOTHING! And the person taking the photos is not obligated to explain him/herself since it is not against the law and it is not a crime. So?

I saw a video (happened in some Brit neighborhood) where a guy was standing on public property taking photos and a police officer started questioning him; the guy said it is not illegal to photograph in public anything that the eyes can see but the police officer insisted in wanting to know why he was photographing; the guy refused to hand over ID, citing that he was not doing anything illegal and was, therefore, not required to show ID. It went on for several minutes until the police officer left, feeling frustrated, no doubt.

For private uses, it isn't illegal since they are on public property, as long as they aren't doing something with expected privacy, along with that the photographer is not invading their privacy. For commercial uses, it is illegal, since they are teenagers they are classified as children or minors, which would require parent knowledge and permission

There are restrictions in certain places that are considered public, but overall it is legal to photograph people in public places. There *may* be local restrictions about photographing minors, and certainly someone doing it a lot should attract the attention of local authorities. Speak to the local police.

It is generally not illegal to photograph children in public in the UK unless they are in the courts.

Can I just add, that none of the pictures are in any way sexual, they are just photos of young boys in the street.

My wife thinks its against the law, but I think its purvey, but not illegal and he is not hurting anyone, as the boys do not know they have been snapped and he is not putting them on line

This is a tough question with many gray areas. Typically, it is illegal unless their parents signed a form of consent. In this particular case, I will let it slide... But only this once. Do not expect any more favors from me after this one.

Yes but yet it continues.some teenage kid took a photo of me when I was trying to use the loo after lunch on Friday

Particularly in England.

Yes it is illegal and same for photographing adults and the same goes for recording them without their permission.

technically - no