I agree that relative poverty is often the wrong measure. Firstly as it is defined (in 2015/6 for a family of 2 adults and 2 children) as 'only' having £1738 per month after housing costs.
www.cpag.org.uk/content/uk-poverty-line
Now, come on, families with £1700 per month to feed, clothe, pay bills, transport etc are not sitting in the dark and eating cold beans.
Granted they're not rich, and probably not even comfortable, but they have enough for a basic standard of living. Obviously there are people well below this level, who are in absolute poverty, but having less than some quite comfortable people doesn't necessarily mean people are absolutely destitute.
Also, based on this definition, the number of people in relative poverty actually went down in the 2007 recession, because median incomes went down more than those of the people at the bottom level of incomes, so while lower income people had the same or less money, they hadn't seen as big a drop as better off people, so some were no longer below the 60% of median, so were therefore 'no longer in poverty' because they had found themselves above a lower goalpost, which is clearly nonsense.