What is the change in producer surplus as a result of the market equilibrium moving from point A to point B in the diagram below?

+£40 thousand+£40\text{ thousand}+£40 thousand
−£40 thousand-£40\text{ thousand}−£40 thousand
+£80 thousand+£80\text{ thousand}+£80 thousand
+£10 thousand+£10\text{ thousand}+£10 thousand