In a Financial Times op-ed, Matthew Engel says
This month, it was revealed that the UK’s Gini coefficient, measuring inequality between rich and poor, had reached its highest level on record — after the longest period of Labour government ever. You do not have to be a Labour voter to wonder what, then, has been the point of it all.
I wouldn’t want to offer a full-scale defense of the Labour governments’ strategy (see ch. 11 of this book for my views), but there is a reasonable response to this particular challenge. Inequality of market incomes has been increasing almost everywhere. Arguably, it has risen less, and government has done more to mitigate its impact, under Labour than would have been the case under the Conservatives. It’s impossible to know that for certain, of course, but the following data on inflation-adjusted income growth during the most recent periods of Conservative and Labour rule are consistent with this assertion.
Lane Kenworthy 
Hi Lane
You’re dead right that the distribution of income gains was far better under Labour than the Conservatives, but in the end there was so much to do that this didn’t prove enough. Labour had a decade of untrammeled power under the Westminster model and rather ‘bottled out’ in the end.
The chart from Brewer et al also gives us a nice clue as to why Labour’s support is collapsing. There was a redistribution from the median voter – or something just to the right of him/her – to the poorer and richer parts of society. The 4th-8th deciles are too big a bunch of voters to mess with, and they would have done better under a less redistributive regime.
A graph entirely consistent with the rich getting richer and the poor remaing, well, poor.