England players have been warned not to use their mobile phones within an hour of kick-off to protect the integrity of the sport as the World Cup reels from the news that Rob Howley has been sent home to Wales.

Howley, Warren Gatland’s number two, is being investigated for an alleged breach of betting and anti-corruption regulations.

Along with every nation competing in Japan, England have been given a detailed 20-minute briefing by World Rugby’s integrity unit that was attended by all players and backroom staff.

Among the steps taken to protect the game are instructions that players must switch off their phones in the build-up to World Cup matches.

It mirrors a similar measure adopted by cricket when phones must be handed in before play and then picked up at the end of the day’s action.

England were told during the briefing on Monday that at the last global showpiece four years ago there were six instances of suspicious approaches being made to players and/or staff.

World Rugby used the case of former Leicester defence coach Phil Blake, who was banned for six months in 2015 for a breach of Rugby Football Union betting rules, to explain the potential repercussions of any wrongdoing.

England assistant coach Neal Hatley expressed his surprise at the Howley news given the briefing Eddie Jones’ squad was given in Miyazaki was the second they had received on the subject in a matter of weeks.

“All the stipulations were set out very, very clearly. I know it gets done at the clubs and the Rugby Players’ Association are actively involved in it so there is real clarity around it,” Hatley said.

“I was a little bit surprised but it’s all very clear, it’s made clear before we arrived and it was made clear two days ago. It’s a real [warning] for everyone at the tournament. A real live reminder.”

England set off for the 941-mile trip to Sapporo on Wednesday as their World Cup opener against Tonga draws closer.

They signed off their final session in Miyazaki with an encouraging injury update after all 31 members of the squad played some part in training with Mako Vunipola (hamstring) and Jack Nowell (ankle) also involved.

Vunipola participated in live scrummaging while Nowell completed sprints down the side of the pitch.

The Saracens prop and Exeter wing are the only players ruled out against Tonga with Jones naming his team on Friday.