Police were called at 11:09hrs on Thursday 5 June to The Shard, St Thomas Street, SE1 after London Fire Brigade were called to reports of a fire at the premises.
Police, London Fire Brigade and London Ambulance Service attended the fire which is beleived to be in the basement of The Shard.
A full evacuation is now underway.
No reported injuries at this time. No arrests. Enquries re cause of fire are ongoing.
More top news
The tribute has been set up to mark the four terrorist atrocities that took place in the city last year.
Six officers opened fire at a property in Hackney in the early hours of Tuesday morning.
A man in his twenties has died from stab wounds after police were called to a disturbance at the Stratford Centre on Tuesday night.