Why the difference in productivity and wage trend in the UK economy? In reading this article from FT, we come across two graphs:



and 



Shouldn't real wages have a similar trend to productivity? Why was there that discrepancy since the 2009 until 2014? Maybe some other factor that shifted the PS, or the WS curve? It's interesting to notice that in Jun 1st 2014 began the sharp fall in oil prices, which may be the cause for the increase in the real wage we've been observing until know. It seems that workers productivity has had little impact in the behaviour of real wages...

Any help would be appreciated.

Edit: I'm including a graph with CPI in GBR with data from OECD.
Blundell, et. al (2014) offer an explanation. According to them, the UK economy experienced a positive labour supply shock over that period.

First, they present the facts in a very intuitive fashion (graph taken from the working paper version):



They argue that the supply shock was due to two factors:


changes in welfare policies that made work more attractive and tightened job-search conditions attached to the receipt of unemployment insurance beneﬁts
an increase in statutory pension age for women that strengthened their labor force attachment


I don't want to infringe copyrights so I won't include more figures, but look at Figure 14 (showing an increase in employment of older workers after the Great Recession), and Figure 15 and 16 (showing an increase in employment participation of Lone Mothers). As the authors state:


  "The age limit for youngest child was set at twelve in November 2008 for all new claimants of Income Support and was lowered to ten in October 2009, seven in October 2010 and five in October 2011." (p. 392)


That is an example of a policy fostering employment participation and a positive supply shock.