The decision to declare Wales prop Tomas Francis fit to face France in the Six Nations in Cardiff on Friday has been described as a "grave mistake".

Professor John Fairclough says selection would put Francis at "unnecessary risk of serious harm".

Wales defence coach Gethin Jenkins expected the trio to train on Monday.

"All three have gone through their concussion protocols and return to play, and all three are expected to be training today and be fit for Friday's game," said Jenkins.

"We always worry when they have to go through protocols. It's quite a stringent process.

"We've lost people in the past due to that, and it's unfortunate. It is a good boost that we have all got three available."

'Francis should not play against France'

Cardiff wing Adams was the victim of a late high tackle from England replacement Joe Marchant which went unpunished, but the incident involving Watkin and Francis caused greater controversy.

The pair sustained head injuries in the 20th minute at Twickenham when they collided while trying to tackle England lock Charlie Ewels.

Both left the field for head injuries assessments (HIA) and passed the tests to return.

The handling of the incident was criticised as a "clear and flagrant breach" of head injury assessment protocol by Progressive Rugby, a lobby group on player protection.

The claims were made in an open letter by Professor Bill Ribbans and Professor Fairclough, who used to work with the Welsh Rugby Union.

Francis struggled back to his feet and leant on the post after the incident before being seen by the Welsh medics.

The letter claimed that "there were 12 Criteria 1 signs and symptoms with six possibly observed on video and the remaining five identified during the on-field assessment".

The two doctors claim "the typical observation on video are confirmed loss of consciousness, suspected loss of consciousness, convulsion, tonic posturing, balance disturbance/ataxia and clearly dazed".

In a separate article, Prof Fairclough has again urged Wales not to pick Francis against France.

"Like any Welsh fan I want to see Tomas Francis in the Welsh team, because he's a terrific player and would be key against a very good French side," said Prof Fairclough.

"But I have carefully reviewed the footage numerous times, and in my expert view, it is beyond any doubt Tomas had suffered a brain injury.

"As someone who has taken an oath to protect life, I can't, in all good conscience, fail to highlight I think him playing the next game puts him at unnecessary risk of serious harm, whether that be now or in the future.

"The HIA protocols undertaken during the England game were shown to be not fit for purpose.

"They were unable to recognise the fact he had clearly sustained criteria 1 signs of on-field concussion.

"The serious features displayed by Francis should outweigh the results of any subsequent assessment indicating he is sufficiently recovered in time to return for the French game.

"Wales may claim that he has been 'passed fit'. For me that would be a grave mistake."

Jenkins says that incident at Twickenham was being still investigated by the Six Nations.

"I don't think the review has been finished yet," said Jenkins.

"We will wait to see what comes of that. I personally didn't see it live. I was more concerned about the poor defence that happened. I saw it after.

"The people in charge and the medical people will have gone through all that, and I am sure the review will see what comes of it."

When asked whether Francis should have played on at Twickenham or play against France with the review ongoing, Jenkins replied: "The HIA process has been in place for a long time now, and players and staff, we all abide by it.

"We've got to back what has happened there, and if anything else comes out of it, it comes out of it.

"The player has passed all the protocols, done his graduated return to play, ticked off all his contact boxes, and he is available for selection."

Navidi back in business

Jenkins welcomed the return of Cardiff flanker Josh Navidi who has been called into the squad after recovering from a long-term shoulder injury.

Navidi, 31, played 80 minutes in his first game in almost five months on Friday in Cardiff's United Rugby Championship away defeat against Ulster on Friday.

"It's pleasing for us to see him come through the game for Cardiff and he's done it before, coming back on the back of not many games," added Jenkins.

"He's a bit ring rusty, but we have confidence his physicality will come back pretty quickly. He'll be looking forward to seeing what selection is."