SAmantha Barber, Executive Director of the Batten Disease Family Association, said: "Today 's announcement will be a relief for all affected families who fought day and night to achieve this result.

"Brineura offers real hope to these children and the priority now must be to ensure that everyone who needs it has access to it as quickly as possible.

"While we recognize the efforts of both sides to reach this agreement, the reality is that it took almost two years to reach this point.

"The human cost of this delay and the anxiety caused can not be underestimated and we hope that efforts will be made to help others avoid this heartache in the future.

"For the moment, we are absolutely delighted with this decision, which is a decisive step in improving the lives of children affected by this devastating disease."

Simon Stevens, Managing Director of NHS England, said: "This is another concrete step to ensure that NHS patients with rare diseases have access to important new treatments.