Thanks for feedback. My friend had numerous occasions where he ended up with dog attacking him in parks in urban areas, this is why I'm curious about it. They're affraid of the dogs in general so situations like this make them anxious for next days. From their experience, dog owners were often behaving like real twats even in clear situations such as being bitten by a free running large dog(s)without close supervision.

Cultural question to Brits as this happened in UK. Do people care if their dog attacks someone or is highly agressive to humans in UK?

By what I've heard from my friends, dog owners often put the blame on attacked/harassed passers-by, they don't feel accountable for their wrongdoings (i.e. not using leash and not paying attention to where their dog is and what is it doing).