LONDON (AP) — British authorities are holding their first major planning exercise for the 2012 London Olympics since riots in the capital last month forced police to reassess their security plans for the games.

The government’s emergency committee, known as COBRA, started a three-day exercise on Wednesday to simulate responses to potential crises during the Olympics, detective chief superintendent Alaric Bonthron of the Metropolitan Police said, “We are going through the whole gamut — from food poisoning to terrorism through to heat waves and rail disruption,” he said. “We have to understand how we manage the games in those situations.”

The violence began in early August after the fatal shooting of a man by police in north London. Police struggled to contain the violence that left a trail of looted stores and burned-out buildings across London, Manchester and Birmingham and led to thousands of arrests.

“We are still reviewing everything post-riots to make sure we have learned the lessons,” Bonthron said.

Britain’s image took a hit during the riots, and a global publicity campaign was launched Thursday to promote the country.

London was already preparing a massive security operation for the Olympics, but most of the attention had been on the threat of international terrorism until the outbreak of unrest.

“We recognize we didn’t always get it right during the rioting,” Bonthron said at an Olympics planning conference. “We are reassessing plans in light of what happened during the riots to make sure the resources we have … match the risk.”

About 12,000 police officers will be on duty each day of the July 27-Aug. 12 games, which have a security budget of $732 million.

The latest in a series of security exercises, which end on Friday, allow the police, government and games organizers to test how their infrastructure could cope with an emergency during the Olympics.

“It’s a simulation where people go through and exercise and test communications, test what sort of responses we need, what sort of information flows we would need … to make sure everyone understand their games-time roles,” Bonthron said. “It’s focused on the response to an incident that could be terrorism or it could be something more minor that could affect the games.”

Meanwhile, London authorities have identified 20 potential risks to the 2012 Olympics. The top four include terrorism, serious crime — specifically ticket fraud — protests and natural disasters such as floods or heat waves.

When the eyes of the world are on London next year, Bonthron can see that “it’s a good time to protest.”

The games also could be disrupted by striking workers. Britain’s public sector unions are planning a huge wave of walkouts on Nov. 30 as they resist efforts to reduce spending on pensions.

“It’s one of the factors being built in (to planning),” Bonthron said. “We, in the police, have issues with our communications staff going on strike. So it’s about looking at all eventualities and trying to plan how we resource and keep everything running if there were to be strikes.”