A woman who twice tried to gain access to a "highly restricted area" in Westminster before dumping two large knives nearby is being sought by Scotland Yard.
Detectives have released CCTV footage showing what they believe is the same woman walking behind gates in the area on two occasions.
The woman attempted to gain access to the area at around 3:30pm on 24 February this year but was refused by police.
The woman in question then returned to the restricted area in a second attempt to gain access 10 minutes later, but was again refused.
Police said a discarded scarf, which is believed to belong to the woman, was later "found on a nearby wall wrapped around two large knives".
Police said this is not being linked to any other incidents at this time, but has released the CCTV footage in a public appeal to help identify the woman, The Guardian reported.
The police statement said: "At around 3.30pm on Tuesday February 24, a woman asked a police officer for access to a highly restricted area, but was refused. Detectives believe this is the same woman recorded on a nearby CCTV camera at around the same time.
"Ten minutes after her first approach she returned to the secure area but again did not gain admission. Later a scarf police believed to be carried by the woman was found on a nearby wall wrapped around two large knives."