A plan to introduce an additional concussion substitute in football rather than temporary head-injury replacements has been described as “hopeless” by the neuropathologist who proved the link between football and dementia.

The International Football Association Board is evaluating a range of proposals to improve concussion protocols and one controversial suggestion that is apparently being given serious consideration is additional permanent substitutes.

This would allow a team to make a further substitution if there was a suspected concussion but would still force medics into making relatively quick on-field decisions that could not then be changed during the game.

Medics are already supposed to remove a player when there is a suspected concussion and Dr Willie Stewart, the Glasgow neuropathologist whose research revealed that former professional players were five times more likely to die of Alzheimer’s, believes that the idea would not result in meaningful improvement.

FIFPro, the world players’ union, has been campaigning since 2014 for the sort of temporary concussion substitutes that have been introduced in rugby union and which allow doctors 10 minutes before deciding whether there is a suspected or confirmed concussion.

Dr Vincent Gouttebarge, FIFPro’s chief medical officer, also wants a minimum six-day return-to-play procedure for players who have been concussed. On-field tests are supposed to be completed within three minutes but are often even quicker. It has led to a series of incidents when players have been allowed to continue before then coming off when they have displayed symptoms of concussion.

The Football Association has advocated the sort of temporary concussion substitutes that are used in rugby and there is concern that this new idea of additional permanent concussion substitutes is gaining traction.

Asked what he thought of the idea, Dr Stewart said: “Hopeless. A way of saying, ‘we’re changing something’ while, in essence, changing nothing. There is no law in the game saying a substitute cannot be used to replace a concussed player – quite the opposite, in fact. At issue is the limitations of the on-field assessment. The real concern is the ability to recognise suspected concussions on-field.”