Nearly two thousand people took part in the Great East swim - among them two Olympic swimmers who are hoping to go for gold in the open water events at London 2012.
Russell Hookey spent the day at Alton Water near Ipswich and saw the action:
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Voting is taking place across the Anglia region in the biggest test of political opinion since the General Election in May 2015.
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There'll barely be a cloud in the sky today and it will feel warm in the sunshine as temperatures reach 19ºC. Frost-free tonight.