The tidal barrier which will protect thousands of homes and businesses from the risk of flooding.
Work on the 38 million pound project in Ipswich started today and it is due to open in 2016.
The council says it will secure the future of the town, and encourage economic growth.
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22 Albatross boats, glamorised by the likes of Brigit Bardot and Prince Rainier, are sailing in Norfolk and Suffolk this weekend.
Risk of heavy rain overnight and later Sunday.
Dry for much of the day. Some rain this evening.