Brain injury charity calls for review of football's concussion policy

The France international appeared to be concussed after a clash of heads with Watford defender Daryl Janmaat in the 27th minute of the Premier League match.

Seven minutes later, a groggy-looking Martial lost the ball in the build-up to Watford's opener and four minutes after that he was substituted.

Headway's spokesman Luke Griggs told Press Association Sport that the charity was not specifically questioning United's treatment of Martial but it was deeply concerned about the general application of the concussion rules football introduced in August 2014.

Those rules were brought in after several high-profile incidents that attracted considerable criticism of football's attitude to head injuries and they stipulate that all home teams must employ a third 'tunnel doctor' to help team doctors identify concussions and decide whether the player is fit to continue.

They also reinforced the Football Association's protocol that a player should even be removed if a concussion is only suspected, but not necessarily confirmed - what Headway refers to as the principle of 'if in doubt, sit it out'.

"Headway welcomed the strengthening of football's approach to concussion when these new rules were introduced, but serious questions now have to be asked about whether they are being fully implemented," said Griggs.

"The role of the independent tunnel doctor needs clarifying. How much influence do they have in decisions about whether or not a player is concussed? Why are they not more visible when these decisions are being taken? Are they actually being consulted?

"The rules state that if a concussion is even suspected the player should be removed and not allowed to return to the game.

"This is a vital detail as concussion can be notoriously difficult to diagnose on the spot - particularly on the pitch with doctors under intense pressure to make big decisions that could influence matches."

Griggs admitted it is very hard to tell if somebody is concussed or not from television pictures and acknowledged that team doctors have to make quick calls in the heat of the moment, but said this is why a "safety-first approach" was so important.

"The danger is that period between the initial injury and the substitution," he added.

"If the concussed player receives a secondary blow to the head in that time, the damage to their brain could be increased significantly.

"Elite-level football has to set a better example for the millions of youngsters around the world who take their lead from their idols.

"We would like to see an independent review of the way in which professional football in this country is implementing its own concussion protocols in order to reduce the risk to not just professional athletes, but also to youngsters and amateurs who do not have doctors on the side of the pitch to provide medical support and advice."

Speaking immediately after the match, Manchester United manager Jose Mourinho said he did not know what injury Martial had when he was forced to come off, suggesting it could have been an ankle, knee or head injury.

Football's response to the growing body of evidence that links head injuries, even minor ones, to serious illnesses later in life has been in the spotlight for some time, most particularly earlier this year when it emerged that four of the eight surviving members of England's World Cup-winning team in 1966 now suffer from dementia or memory loss.