Pc Blakelock, who was 40, was attacked and stabbed dozens of times as he tried to protect firefighters tackling a blaze at a supermarket, during the height of the Broadwater Farm riots in 1985.
Nicholas Jacobs, 44, who is accused of killing him, will appear at Westminster Magistrates' Court tomorrow.
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The pub owner said the sign is a nod at having a bit of fun in support of them and celebrating their relationship and the wedding.
A 61-year-old woman was taken to hospital with head injuries after the incident in Islington, north London.
Assema Kedir Habib spoke at the commemoration of her brother Hashim Kedir and his family.