British bobbies are being told to put on the "happy face of policing" at the Olympics.
Summer leave has been slashed by half at Scotland Yard, with officers being asked to change their shift patterns to work longer hours.
But police will be told to put aside additional discontent over pay freezes as millions of sports fans flood the capital.
Assistant Commissioner Chris Allison tells them to enjoy policing the games and be "happy" in internal briefing documents seen by London's Evening Standard.
Mr Allison, who is in charge of security for the Olympics, said: "We are saying you are here to do your job, prevent crime and maintain the Queen's peace but at the same time enjoy it.
"This is about us engaging with people and being a happy face of policing. It is a once-in-a-lifetime experience for all of us."
The Games mark the biggest peacetime policing operation in history.
The Metropolitan Police will deploy 6,000 officers out of a 12,000-strong Olympic force across the UK.