Supt Kevin Purcell, of West Mercia Police has said four children were playing near the lock, but two fell in and another then went to try and get them out, while the fourth ran home to raise the alarm.
This video shows the canal where three children entered the water. Police say they are 'working hard to establish exactly how Imie came to be in the water'.
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Remaining dry overnight with lengthy clear periods.
Leah Washington, 17, had to have her left leg amputated after being trapped for hours on The Smiler rollercoaster at the theme park.
Fine and dry this evening and overnight with showers on Sunday afternoon.