The police, fearing they are perceived as too soft, are asking the British government to make flag-burning a crime as part of get-tough moves on Muslim extremists and others who sow religious hatred.
Tarique Ghaffur, the Metropolitan Police's most senior Muslim officer, told BBC radio that the proposal is among several submitted to Attorney General Lord Peter Goldsmith, the government's chief legal adviser.
Others include restrictions on the contents of protest banners as well as a ban on masks in order to prevent extremists from hiding from the police, said Ghaffur, who is the assistant commissioner in charge of public order in London.
"There appears to be a growing public perception that policing of demonstrations is unduly lenient," Ghaffur said. "That view was shared by law-abiding citizens of all backgrounds."
"The reason this is a great country is the tolerance of people," he added.
If people "start to see images of people who seem to be `getting away with it,'" then people's tolerance "starts to erode," he said.
The police wanted "a change in the law on the burning of flags -- to make that illegal," he said.
The attorney general is preparing a package of announcements for next month, according to a source close to Goldsmith quoted by the BBC.
It said these are being debated among ministers who will decide how far existing laws can be used more effectively and consider police calls for changes in the law.
Ghaffur, who has been consulting with Lord Goldsmith, warned that senior officers are prepared to be firm with flag burners and extremists exploiting protests, whether or not the police appeals are heeded.
The senior officer told BBC radio that the proposals would be backed by the Muslim community because they clearly targeted the extremist minority.
However, the police proposals immediately triggered a debate.
The proposals are "unnecessary," according to Shami Chakrabarti, director of the civil rights group Liberty.
"We will have to look at the detail of these proposals but the police already have wide powers, especially for dealing with people wearing masks," she said.