Effect of stellar flares on the upper atmospheres of HD 189733b and HD 209458b

United Kingdom Natural Environment Research Council (NERC) [NE/N004051/1]; UK Science & Technology Facilities Council (STFC) [ST/K001051/1, ST/N000692/1]; SFTC [ST/K001051/1, ST/J500616/1]; Spanish MINECO [AYA2011-30147-C03-03]