Anthony CarrollA major exercise was held in Great Yarmouth in the early hours of yesterday morning to test the readiness and robustness of temporary flood defences..Anthony Carroll

A major exercise was held in Great Yarmouth in the early hours of yesterday morning to test the readiness and robustness of temporary flood defences.

In just one hour Environment Agency staff set up a 75m long barrier along Bollard Quay on Southtown Road to simulate a response to a shipping disaster.

Working under flood lights and on their hands and knees in cold conditions, 10 staff installed the new type of barrier which can hold back 1.2m of water.

Exercise Marsh Harrier demonstrated how quickly the Environment Agency can set up a temporary barrier in the event of some of the town's 4km of flood wall being demolished by a ship.

Every year about two incidents are reported in Yarmouth of manoeuvring ships damaging sections of wall.

Last year it took the Environment Agency five weeks and �30,000 to repair part of a wall that had been badly damaged by a vessel.

Yesterday's exercise was a worse case scenario involving a whole section of flood defences being destroyed just as a tidal surge was expected to hit the town.

It was anticipated that it may take two hours to install the new style temporary Geodesign barrier so one of the exercise coordinators

The Environment Agency has a store of 200m of the Geodesign barrier that can be delivered to Yarmouth within an hour and a half of a flood wall emergency.

In the event of a major event the agency also has a 2km stretch of barrier, which was used in the Tewkesbury floods of 2007, that can be sent to Yarmouth within hours of a ship smashing down large sections of wall.