The Chelsea pair were forced into self-isolation as a precaution after coming into contact with Scotland midfielder and clubmate Billy Gilmour – who has tested positive for Covid-19 – on Friday night.
And it was confirmed this morning that neither will be available for England’s final Group D game at Wembley, leaving a shadow hanging over the Three Lions’ preparations.
They will have to isolate up to and including Monday June 28, which will see them train individually at St George’s Park.
Jude Bellingham is likely to come in as a replacement for Mount after Gareth Southgate was forced to make late changes to his planned starting XI.
England have already qualified for the knockout stages, but will play their round of 16 tie on Sunday, Monday or Tuesday, dependent on tonight’s result. But the isolation means Mount and Chilwell would not be available for that game unless it is played on the Tuesday.
Defeat for Southgate’s team would mean they have played their last part in these Euros.
Even though the pair have both tested negative – along with the rest of the England camp – the concern for Southgate and his medical team is that it could take some time for a positive result to return. That would heighten the risk of coronavirus spreading through the squad if they are re-integrated.
In a statement the FA said: “Chilwell and Mount will isolate and train individually in private areas at England’s training base St. George’s Park, with the squad returning there after tonight’s fixture against Czech Republic at Wembley.
“We will continue to follow all Covid-19 protocols and the UEFA testing regime, while remaining in close contact with PHE.
“The entire England squad and staff had lateral flow tests on Monday and all were again negative, as was the case with Sunday’s UEFA pre-match PCR tests.”
Southgate said: “We know these things can appear four or five days down the line so that’s what we’ve been living with all year in a football-sense. Every time we are tested you are trying to do everything right across the camp.
“We have had nothing all year, but we know a lot of that has been good practice, but some of that has been good fortune.
Mount and Chilwell were isolated after chatting with Gilmour in the moments after England’s 0-0 draw with Scotland.
Southgate says players will be reminded of protocols going forward.
“We’ve always known we’re trying to be as vigilant as possible, but there’s always an element of fortune about these situations as well,” he added. “We don’t know exactly where everything sits on this one yet.
“Of course it’s not ideal, but we’ve always known this could happen and every team has been sort of living with this fear and some have already had to deal with it. We’re the latest to have to have that disruption and we’ve just got to get on and deal with it.
“The protocols – it would be something to do with chatting after the game, but I have no idea of all the detail. That’s why we’ve taken the decision at this point to isolate them. That’s why we’re having to have the discussions with Public Health England,
“I think these sorts of things do serve as a reminder that we are under a different sort of spotlight to most parts of the community and at higher risk of being forced to miss matches or whatever else. I think the players, after what’s happened today, I don’t think they will need us to tell them, but for sure we will.”
Meanwhile, Southgate is convinced he is the man to get Harry Kane firing again.
He said: “Throughout the time I’ve been England manager, I must have answered these sorts of questions about Harry on three or four different periods of time.
“And inevitably he’s come through those periods and scored important goals for us and played exceptionally well, so it’s a bit of a repetitive cycle.
“The big players have big focus, have a lot more attention and their world is far more complicated than a lot of other players, who can sort of go under that radar of pressure and intensity.
“I’ve got a huge understanding of how that is for Harry, a huge understanding of having played with big personalities, big players, how their world is different.
“Hopefully that helps me to manage him and to get the best out of him, which I think over a long period of time we have done.”