The Football Association’s head of security has warned of more trouble when England travel to Prague to play the Czech Republic on a Friday night in October – and said the authorities may have to reconsider when to play such games in the future.

Tony Conniford admitted he was “deeply embarrassed” by the bad behaviour of a section of England fans who threw bottles at police in Porto and were abusive to locals – and conceded it could easily happen again the next time England travel abroad.

“Prague on a Friday night. I am not going to stand here and say I am confident about that because I’m not,” he said. “Prague is a well-known city for welcoming stag dos. I think it’s tried to change that image but that is a concern for me.

“Perhaps moving forward, when draws like that are made, like we do in England, if there is a potential issue then perhaps the authorities need to look at that and say: ‘Is England travelling to the Czech Republic on a Friday night the best thing for the game?’”

Conniford also admitted he was increasingly concerned about far-right groups such as the English Defence League attaching themselves to the national team because it was “fashionable” and tarnishing its image as a result.

“I’m extremely worried that we’ve got the groups that I saw on social media, and the images portrayed across the world associating themselves with the national team,” he said. “Because that causes me problems when I go to a country.

“For example, we’re going to Kosovo, where England haven’t played before. I’ve been to countries where their briefing to police officers is to show them footage of that sort of behaviour. That ups the ante straight away. So fans are met with riot police and dogs before they even get off the plane.

“We got rid of that. We turned it around so people were welcome. So yes, I’m worried about those groups tarnishing what we achieved. Do I know the solution? I don’t in this moment in time and I’d be lying to you if I said I did.”

Conniford, however, praised the Portuguese police who he hailed for doing everything possible to help England fans enjoy the Nations League.

“It has been a real disappointment for me because I asked the supporters to respect the country. Sadly a group decided they weren’t going to do that. I want genuine people to come and everything was laid on for this to be a special event and unfortunately what we saw the other night deeply embarrassed me as an Englishman and didn’t bring us any favours.”