(01 of15)
Open Image ModalA scuffle with police during a '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(02 of15)
Open Image ModalA man smoking at the '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(03 of15)
Open Image ModalA man wearing a President Obama mask holding a giant spliff attending a '420 Celebration' pro-cannabis event - organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(04 of15)
Open Image ModalA man is searched at an entrance to Hyde Park, central London, during a '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner. (credit:Yui Mok/PA Wire)
(05 of15)
Open Image ModalA '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(06 of15)
Open Image ModalA '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(07 of15)
Open Image ModalA '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(08 of15)
Open Image ModalA man is searched at an entrance to Hyde Park, central London, during a '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner. (credit:Yui Mok/PA Wire)
(09 of15)
Open Image ModalA man is searched at an entrance to Hyde Park, central London, during a'420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner. (credit:Yui Mok/PA Wire)
(10 of15)
Open Image ModalA '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(11 of15)
Open Image ModalPolice officers at a '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(12 of15)
Open Image ModalA man smoking during a '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(13 of15)
Open Image ModalA '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(14 of15)
Open Image ModalA '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)
(15 of15)
Open Image ModalA '420 Celebration' pro-cannabis event organised by Norml-UK, a group seeking to reform British cannabis laws - at Speakers' Corner in Hyde Park, central London. (credit:Yui Mok/PA Wire)