Commissioner Dick was in charge of the police operation which resulted in the fatal shooting of Jean Charles de Menezes at Stockwell Tube station in 2005.
She will replace outgoing Commissioner Bernard Hogan-Howe.
Sian Berry said:
“This is a very controversial choice. Assembly members will want questions answered about the lessons the new Commissioner learned after the Jean Charles De Menezes shooting.
“This was the most serious and shocking single mistake the Met has made in the last 20 years. For the Mayor to appoint the officer in charge on that day to run the whole of the Met when community cohesion is his priority for London does potentially put this at risk.
“Londoners must have complete confidence in their police force and its leaders – I will be questioning the Mayor about this appointment.”
Cressida Dick was Commander of the Met’s counter-terrorism unit who authorized the killing of Jean Charles DeMenezes at Stockwell tube station in 2005. DeMenezes was an innocent Brazilian electrician on his way to work, but was identified by the colour of his skin to be a Middle-Eastern terrorist.
The Menezes family have protested that the appointment of Dick “sends the wrong message…”.