Hello everyone.
Maybe it's sounds stupid but I need some photo knowledge and experience. I would go as free assistant with professional photographer in studio or at location. So if somebody need assistant in London for free let me know
How experienced are you? A professional photographer wants an assistant - which means they want someone who doesn't need teaching anything. An assistant is there to do stuff the photographer doesn't have time to do, and it's a lot more than carrying bags and making tea. You'll be expected to set up lights, and meter lights to instructions, process raw files, possibly retouch... pretty much anything the photographer themselves would do. What photographers want as an assistant is another photographer.
You'd be better off being honest as saying you want to work for free to learn stuff, and not pass yourself off as an assistant. Photographic assistant is an actual job role with a required skill set.. not someone who carries stuff... although you will be carrying a lot of stuff

Like many people, assisting was my first role after graduating and my first job was in house assistant in the famous Holborn Studios... a real baptism by fire, but I had the advantage of already working as a professional photographer for years before I finally went back to college to get a degree. While most big names have their own assistants, I was often seconded to many big names on many big shoots, so it was still stressful. All I can say is that if I didn't know what I was doing, I'd have not lasted a day. That's a bit of a pressure cooker environment though, but even if you're just assisting a local social portraiture photographer, they will not want someone who is more of a liability than assistant. They'll expect to have the job done, and not spend time teaching you things you should already know.
Be honest... stop saying your an assistant if you're not, and instead just ask for someone to mentor you... then you'll both know what to expect from one another.
If you're already experienced.. then scratch everything I've just said, but in all probability, if you needed to ask this question, you're probably not.