from Northamptonshire Police Rescue Team yesterday:
UK water temperatures are 10-15°C, even in summer.
This is chilly enough to cause cold water shock, making you gasp uncontrollably and breathe in water which can quickly lead to drowning.
Cold water can affect your ability to swim out of trouble.
Advice from other Forces as the 3rd body is pulled from the Thames this week is not to dive into water as this can cause shock but to wade in slowly, checking the river bed, always wear shoes for extra protection against sharp objects and to allow the body to adjust to temperature changes B4 immersion.