The Resolution Foundation has referred to stagnation generation and raised concerns that millennials will earn less than previous generations. See its new website the Intergenerational Commission which is examining fairness between generations.
Another good starting point for examining issues relating to this is the IFS website . This week it published a report on Living standards, poverty and inequality in the UK which reviewed trends for the last 50 years. In November 2015 they also published a report on wealth in the UK.
The Equality and Human Rights Commission Report Is Britain Fairer report? also reviewed evidence of a decline in social mobility in modern UK.