Brooks Cascadia 10 at TK Maxx online for £29.99. Never used them, but for that price I'm willing to take a punt!
http://www.tkmaxx.com/mens-trainers/.../invt/38001554
http://www.tkmaxx.com/womens-trainer.../invt/38003466
http://www.tkmaxx.com/mens-trainers/.../invt/38000766