Environment Agency engineers were demonstrating the latest portable flood defences today, as Exercise Watermark got under way in King's Lynn.

Britain's biggest-ever civil defence drill, involving more than 10,000 people, is under way this week.

Tomorrow EA engineeers and members of the emergency services will simulate a repeat of the conditions which caussed the 1953 floods, to test how they and other bodies like councils and the NHS react.

Today engineers at the EA's Lynn depot - who maintain defences from the north Norfolk coast to the Fens - showed how their lightweight barrier can be used to protect vulnerable buildings or plug gaps.

They deployed a section of the defences around King Staithe Square in under an hour and also closed some of the dam boards around the Purfleet.

EA operations team leader Alan Daniels said: 'The tide normally comes in at King's Lynn below four metres. When it is forecast to rise above four metres, our workforce is out shutting some or all of the 54 flood gates and 18 dam boards that help protect King's Lynn.

'What we're doing today is part of the regular testing and checking of both equipment and procedures that we do with our partners to make sure we can operate the gates effectively and quickly when we need to.'

Lynn suffered worse flooding in 1978 than 1953, as marks on the wall of nearby St Margaret's Church testify.

Roy Johnston, the borough council's portfolio holder for performance remembers the town's '78 soaking, when the Ouse overflowed onto the Quays, King Street and the town's medieval quarter.

'We're much more prepared now,' he said, as engineers put the finishing touches to the barrier section.

'I'm very happy to see it all, it's very impressive. This is the kind of equipment they used at Tewkesbury.'

Tomorrow there will be exercises taking place in Wells, Sea Palling, Potter Heigham and Great Yarmouth. See tomorrow's EDP for full story.