Speaking about the debate, which she attended, Nelson said she was devastated that the issue wasn't being tackled with more urgency.

"I cannot tell you how heartbreaking it is to know that my children's lives could have looked completely different," she said, fighting back tears.

"They could have been walking by now. They didn't have to be on breathing machines.

"I have to give them medicine every four hours. I have to turn them every two hours, because they can't do that themselves. I have to make sure they're not choking... because this disease has affected their muscles with their swallowing.

"To know that there are people that are literally making this decision to make children suffer... I have no words."

The singer also recounted showing Hodgson a video after the debate, featuring two sisters living with SMA - one who received treatment, and one who did not.

"One is in a wheelchair, the other is running along, pulling her sister along," she said.

Nelson claimed Hodgson was surprised by the video, admitting she hadn't realised the full extent of early treatment's impact.

"How do we have the health minister standing up in parliament arguing why this should not be rolled out across the whole of England, when she doesn't even know how life-changing this treatment is?" Nelson asked.

The charity Muscular Dystrophy UK welcomed Monday's debate, saying it was "encouraging and moving to hear many MPs speaking passionately about SMA newborn screening".

However, it added: "We'll continue to push the UK government to roll out screening in every part of the UK. No more postcode lottery."