Lawyers acting in head injury claims for retired sportspeople have added another batch of 50 individual cases to proceedings.

The service by London practice Rylands Garth comes despite an ongoing Solicitors Regulation Authority probe into allegations from a former rugby player that he felt pressured into joining a group claim despite not suffering any injury.

The firm said it now represents 850 former amateur and professional rugby union and league players who are part of legal actions against governing bodies, or who are in the process of being tested for potential brain injury. The number of players involved in the claim has almost doubled this year.

A spokesperson for Rylands Garth said: ‘The players we represent were systematically failed by their governing bodies and, as a result, now find themselves dealing with the life-altering consequences. The severe neurological injuries our players suffer with affect every aspect of daily life for them and their families.’

The claimants contend that governing bodies failed to protect them from concussion-related injuries and long-term neurological impairments sustained during their playing careers.

The next case management hearing for the rugby cases will be held on 4 and 5 February, where Rylands Garth will advocate for the players’ cases to be heard jointly as a Group Litigation Order.

A further 65 former football players are involved in a separate claim, although proceedings have yet to be issued for some of these individuals. A case management hearing for these cases is due for 29 January.

The firm’s activity appears to be undiminished by allegations by retired Wasps and England prop Will Green. He told the Telegraph that he had been repeatedly pressed to join the firm’s action against rugby authorities regardless of medical reports showing no signs of a brain injury.

Green ended his involvement with Rylands Garth and was then taken to court for repayment of legal and medical costs. The claim against him was dismissed.

An SRA spokesperson said: ‘Following additional information in the court case, we can confirm that we will be looking into this before deciding on next steps.’

Rylands Garth said it had asked Green to pay for some of the costs of tests by two experienced neuro-specialists, in line with its letter of engagement.