As the United Kingdom prepares to mark the 10-year anniversary of the 7/7 attacks and is still reeling from a terror rampage on a Tunisia beach resort in which at least 30 Britons were killed last month, London police are being criticized for failing to arrest a man wandering around a major site draped in an Islamic State flag.

The man was photographed by tourists on Sunday walking near Big Ben and the Houses of Parliament, wrapped in the flag and with a small child hoisted on his shoulders waving a smaller version of it.

The police told The Guardian that its officers saw the man and even spoke to him, but decided not to arrest him because he was not committing a criminal offense.

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“The man was spoken to by officers, with consideration given to relevant legislation, particularly the Public Order Act. The decision was taken by officers at the time that the man was acting within the law. He was not arrested,” the police said in a statement.

“Wearing, carrying or displaying of an emblem or flag, by itself, is not an offence unless the way in which, or the circumstance in which, the emblem is worn, carried or displayed is such as to cause reasonable suspicion that the person is a supporter or member of a proscribed organization.

“While support of and membership of ISIS is unlawful it is not a criminal offence to advocate the creation of an independent state,” it went on.

A Home Office spokesman told the Daily Mail that “ISIS is a proscribed group. Showing signs you are a supporter of that group is an offense. It was an operational decision and we cannot comment on individual cases.”

Britons took to social media to express their concern with the lack of police action in this matter.

The display came about a week after 38 people were gunned down by IS terrorist Seifeddine Rezgui on a beach resort in Sousse, Tunisia. The majority of the victims were British citizens.