According to a tweet by Kantar World Panel the Nokia Lumia 520 has helped Nokia’s market share rise to its highest position in the UK since April 2011, when they had 11.4% of the market. We can also assume the most recent figures will be over 10.7% which were achieved in the 3 months leading up to June 2011 (credit to NokiaPowerUser and its readers for that research).
KWP publish their results on a monthly basis, with their figures accounting for 3 months. Their latest published figures up to May 2013 had Windows Phone at 7.8% of which Nokia handsets make up roughly 85%.
It will be interesting to see when the whole figures for the 3 months up to June 2013 are released.