England fans involved in scenes of unrest in Porto have been slammed for "completely unacceptable" behaviour by the UK's head of football policing.
Travelling supporters arrived in the Portuguese city earlier this week ahead of Gareth Southgate's side taking on Netherlands in the semi-finals of the inaugural Nations League Finals on Thursday.
Following an instance of anti-social behaviour outside a bar on Tuesday, riot police charged England fans after bottles were thrown at a Porto fan zone on Avenida dos Aliados, where Portugal fans were gathering to watch their team's 3-1 win over Switzerland.