This video shows Dame Helen Mirren, dressed in her costume as the Queen, confronting the drummers outside the Gielgud theatre in London.
The footage was filmed by comedian Chris Dangerfield who lives in Soho.
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Passengers looked horrified as the girl took the potentially lethal shortcut between platforms.
Police were called to Kilburn High Road at 5.20pm after reports of a shooting.
In just 24 hours the offer was retweeted more than a thousand times on Twitter.