The main themes in Blood Brothers are connected with differences in social class, and the effects these have on the lives of the main characters.
Although superstition and fate are presented as themes, the political message of the play seems to be saying that it is real-world social forces that shape people's lives.
The themes within any literary work are the underlying ideas that probably prompted the work to be created. We know that Russell enjoyed music and had his roots in the working class North. We can guess, too, that he was critical of certain political ideas and felt there were definite wrongs in society.
Creating a play that might end up being viewed by tens of thousands might seem to him a particularly effective way not just of gaining wealth and fame but also as a way of getting his ideas across in a persuasive and influential way.
Family and friendship for characters from two different social classes form the heart of the play. Russell shows how wealth brings privilege, even down to the way the Johnstone's and the Lyons are treated differently by the law.
The four main characters can be seen to be social stereotypes, presented dramatically in order to emphasise certain important differences in social class. Russell does this to show the unfairness that it results in.
The individual and society
In the play Russell illustrates the influence that society has on individuals, in their education, behaviour and the opportunities they have. When Mickey says at the end of the play ‘I could have been him’, the audience become aware of just how differently life might have turned out for him if he had been brought up within the Lyons family.
Nature vs. Nurture
The 'nature versus nurture' debate is about how much a persons life is determined by their inherited genetics (their 'nature') and how much is determined by the environment they grow up in ('nurture'). The boys are identical twins and so the difference in the way their lives turn out must be a result of their different upbringings and social positions. Russell uses the twins idea to persuade us that attitudes in society influence peoples lives more than their individual efforts at wanting to do well.
Russell's play is deliberately objecting to a view that was popular in the UK at the time the play was written. Margaret Thatcher's right wing conservative government claimed that everyone who wanted to work hard could be successful. But Russell clearly objects to this view.
Fate, bad luck and destiny
Each of the major characters is presented as being trapped and plagued by various…