Esther said she noticed more security but was unsure "what they would really be able to do" in an emergency.
The 24-year-old said: "Yesterday I saw two of them - an older man and a young girl. I'm grateful for their communal service, but how exactly would they be of use in combatting a terrorist threat?"
Security in the capital was upped after an Israeli tourist was injured in a stabbing attack in central London. An American woman was murdered in the attack in Russell Square on Thursday.
Yovel Lewkowski, 18, from Tel Aviv, described how she watched in horror as the knife-wielding attacker went on the rampage.
On her Facebook page she wrote that the American victim, 62-year-old Darlene Horton, “perished in front of my eyes” in a “matter of seconds”
A 19-year-old man, who is a Norwegian national of Somali origin, was arrested on suspicion of murder, after a Taser was used to detain him.
Police said mental health was a "significant factor" in the incident.
