There is a small hole low down in the back of your fridge, through which condensation on the back of the fridge drains to an evaporating plate on top of the motor.
See these:
http://www.hotpointservice.co.uk/appliances/fridges/how-to-videos/
https://www.youtube.com/watch?v=wJ7bee0ZcAM
https://www.youtube.com/watch?v=8H3wSU7t-Iw
https://www.youtube.com/watch?v=du_99JIAUz0
https://www.youtube.com/watch?v=HHr7bCO_IiA
http://shop.electrolux.co.uk/product/50214722006/Fridge+Drain+Hole+Cleaning+Device
http://forums.moneysavingexpert.com/showthread.php?p=29417
If you have a bit of the old-fashioned plastic covered spring that people used too hang net curtains from, that is really useful fo rclearing out the draininge hole (This kind of stuff: http://www.amazon.co.uk/Curtain-Wire-Metre-Length-Hooks/dp/B002Z8GZ0Y)
XXXXX, September 2015