Thousands of police officers will be asked if they want to be routinely armed in a major survey launched on Monday.
All members of the Metropolitan Police Federation will have the opportunity to state whether they would be willing to carry a gun or a Taser.
They will also be asked if the prospect of being armed at all times would put them off the job altogether.
Last year Scotland Yard announced plans to increase the number of firearms officers on hand to protect the capital by 600 in the wake of the Paris terrorist attacks in November 2015. Nationally the armed policing strength is being boosted by 1,500 personnel.
Now the Met Police Federation, which represents 32,000 officers in London, is asking all of its members whether or not they would be happy to be armed on duty.
Ken Marsh, chairman of the association, said: "We're not an armed force, we never have been.
"But the terrorism threat in London is constant and our officers must be vigilant and be able to deal swiftly with any scenarios we face.
"We are moving closer towards that by arming 600 more officers and I think it's only fair that we ask our colleagues - who go out there on a daily basis - what they want. "
He said the results of the survey - which runs until the end of January - could have a "lot of implications", including the prospect of officers having to pass harder fitness tests to be armed.
"This is not about just giving someone a gun and saying 'get out there', this is about the full requisite requirement of being, let's say, an SO19 officer, everything that goes with that, so there's a huge amount of work that would need to be done," he added.
Questions for those taking part in the survey cover both Tasers and firearms, including whether they would want to carry them at all times on duty.
On firearms, officers will be asked for their views on whether they think there should be more officers carrying guns in London.
They will also be asked if the thought of carrying a gun would make them leave the job.
Most police personnel in the UK are unarmed, setting the country apart from most other nations around the world.
But the question of whether officers should carry guns as a matter of course has been debated for decades, and the issue has come under scrutiny again after recent atrocities in Europe.
Previous research has suggested the majority of police are opposed to any change in approach, but surveys of members of the public have proved less conclusive.
A poll in the wake of the Paris attacks found 58% of people believed officers should be routinely armed.
For more than two years the official threat level for international terrorism in the UK has stood at severe, meaning an attack is "highly likely".
The Met Police Federation is being allowed to use the Met's systems for the poll but Scotland Yard said the survey is not being carried out on behalf of, or in partnership with, the force.
A Scotland Yard spokesman said: "The position of the Met and the Commissioner is clear - we are proud to maintain the tradition that police in this country are not routinely armed. The routine arming of the Metropolitan Police is not supported.
"About 92% of the service is unarmed and armed policing is delivered by highly-trained specialist units. There is no plan to seek to change this.
"Twice in recent years the Met has increased the number of specially-trained officers who carry Taser, and this is kept under constant review.
"We always want to know what our officers think about issues that deal with their personal safety, as it is, and will always be, a huge priority for the MPS."