All the characters in J.B. Priestley's play apart from the Inspector and Edna played a part in Eva Smith/Daisy Renton's life and contributed to her death. Some characters played larger parts in the life of Eva Smith than others. For example, Gerald played a larger part in the life of Eva Smith than Mr Birling because he knew her personally for a much longer period of time. Even so, I believe that the parts the characters played in Eva Smith's life were just as important as each other. This is because all of their actions formed a chain of events....
answer by saying,

"Just what I was going to ask!" P.37, Act Two.

The Inspector isn't there to convict any of the characters. He is there simply to make them realise what they have done. Perhaps in the hope that they will change their ways. This is something I have discussed as one of the themes of the play. That people realise their mistakes and changed for the better. The First and Second World Wars are examples of not doing this. Failing to prevent a Second World War cost many people their lives. By Lee Haywood.