A number of clubs had already cancelled plans to hold in-person press conferences this week, only a few weeks after such conferences were allowed again.

Telegraph Sport understands that some teams were tightening restrictions at their training grounds before the league’s call for a return to emergency measures.

The numbers of staff who are allowed to attend training grounds has already been reduced in some cases, while there has been renewed focus on preventing crossover between different teams at the same club. The emergency measures include tighter rules on social distancing and mask-wearing.

Ralph Hasenhuttl, the Southampton manager, disclosed on Thursday that the club are now restricting social events for their players and stopping families from mingling after matches.

“We had one situation where players went out for a dinner,” Hasenhuttl said. “We had a few issues with this dinner and we’ve tried to avoid these things for a long time.

“Also we had the behaviour of players meeting after a game with the families, which we stopped. It is not possible at the moment. We have to be very careful of not getting any risk of losing a player with the virus.”

Meanwhile, Claudio Ranieri, the Watford manager, has urged all his players to get vaccinated before the start of the busy Christmas period. “I think the important thing is all the players must be vaccinated, because we play every three days now and we meet a lot of players,” he said.

The postponement of Tottenham’s match against Rennes, which was formally confirmed by Uefa on Thursday morning, has prompted complaints from the French club and from Vitesse Arnhem, who are in the same Europa Conference League group.

Vitesse are vying with Tottenham to finish second in the group and the Dutch club have bemoaned the loss of a “fair, simultaneous battle” between the two sides.

Tottenham’s match against Rennes was due to be played at the same time as Vitesse’s meeting with NS Mura, with Vitesse saying on Thursday that the postponement of the match in London has put them at a “significant disadvantage” from a sporting perspective.

“A fair course of competition must be guaranteed at all times,” Vitesse said in a statement. “Vitesse and Tottenham Hotspur compete for a place in the knockout phase of the Conference League and that must be a fair, simultaneous battle.

“If Tottenham Hotspur v Stade Rennais are moved to a later moment, that will be a significant disadvantage for Vitesse from a sporting point of view, because both teams are highly dependent on each other’s result.”