Some MPs, including Ulster Unionists who may need guns for self-defence in their constituencies, have asked permission to use the weapons at the Commons.
They want to use the rifle range run by a shooting club for MPs and peers inside the Palace of Westminster.
The rifle range is housed in the bowels of the Victorian palace, close to the spot where Guy Fawkes and the conspirators placed their gunpowder kegs.
The Yeomen of the Guard - armed with nothing more lethal than halberds - traditionally inspect the basement each year before the State Opening of Parliament to ensure against any modern gunpowder plot.
For years, MPs and peers have been using the range along with House of Commons staff, including police officers, for regular target practice with rifles.
The shooters have included Edwina Currie, the former Health Minister. Shooting at hooped cardboard targets with .22 rifles is seen by some MPs as a sure way of forgetting the cares of their job, and overcoming the frustrations of life on the back benches.
Now the MPs' Westminster rifle club has applied for permission to use pistols in addition to rifles when MPs return to the Commons after their Christmas recess.
The House authorities have delayed making a decision over fears about security. They are concerned about the risks involved in having pistols in the Palace of Westminster.
The only Prime Minister to be assassinated - Spencer Perceval - was shot with a pistol in the Members' Lobby on 11 May 1812.Reuse content