A replica of the destroyed Arch of Triumph in Syria's city of Palmyra, set in front of the National Portrait Gallery, after being unveiled on Tuesday to a crowd of hundreds in Trafalgar Square in central London.

The original arch was blown up by the Islamic State in Iraq and Syria (ISIS) militant group after it took over the ancient city last year, and the 6m-tall scale re-creation was crafted using the latest 3-D printing and carving technologies by the Oxford-based Institute for Digital Archaeology.

It will be on display until today before travelling to New York and Dubai for further public displays.

Palmyra, a Unesco World Heritage Site north-east of Damascus, was taken back by the Syrian army from ISIS last month.

The remains of the arch, dating back to the era of Roman Emperor Severus in the third century, are now scattered on the ground, with only the two columns that once sustained the central crown still standing.