Members of the public can expect to see activity at Sandrocks, near Haywards Heath, which is a disused building.

Traffic will be entering and leaving the site from around 7am to 8pm next Tuesday and Wednesday (July 7 to July 8) while officers recover 'bodies'.

The area is not overlooked by the public and officers will be guarding the site.

A temporary mortuary set up at Woodvale Crematorium, on the Gyratory/Lewes Road in Brighton. From Monday (July 6) from about 6am.

Around 14 Portakabins will be taken to the site, which may cause some disruption to traffic.

From Wednesday morning through to Thursday afternoon (July 8 to July 9) there will be significant police activity at the crematorium.

Detective Inspector Neil Fellingham, who is organising the exercise – called Operation Sandrocks – said: "We hope this will only cause minimum disruption to members of the public but we want to make them aware of what is happening and the fact that this is an exercise and not a real incident.

"It will involve a number of different agencies from across Sussex and the South East region and the aim is to test us on our capability of dealing with a mass fatality incident. Of course we hope that something like this doesn't become a reality, but in the event that it did we need to ensure that we are as equipped and able to deal with it as we possibly can be."