The government has said it will maintain emergency policing levels in London through the weekend, and beyond if necessary.
"The neighbourhood policing levels have been decimated, the safer neighbourhood teams that existed at ward level, identifiable officers that people could call and who they knew," said Lammy.
It works well for a time, he argues, in densely populated areas with relatively high policing levels and large amounts of petty crime.
The Metropolitan police said they had not received complaints of specific threats and would have "appropriate policing levels as for any premiere at Leicester Square" but were "flexible if something more needs to be done".
The researchers controlled for other potential explanations, including changes in policing levels and incarceration rates, and the sharp increase was unique to the region and out of keeping with crime trends nationally.
The chancellor was keen to emphasise that public spending cuts would be at half the rate of the last parliament and there were middle England give aways on museums, sport and policing levels.
If elected I will use my experience and every lever available to get the best for London, to work to hold down fares, build homes, protect policing levels and defend investment in public transport.
"In the control states, homicide rates tumbled in the mid '90s — but in Connecticut, the gun homicide rate fell faster and farther, even after controlling for demographic changes, incomes and policing levels".
It finds a "modest inverse association" between policing levels and four crime types: homicide, robbery, assault, and burglary.
The correlation between policing levels and violent crime in the UK is "very weak", it concludes.
