A mother from Watford who was forced to sell her home to pay for “life-changing” medicinal cannabis to treat her severely epileptic daughter has urged Boris Johnson to make the treatment more accessible.

Elaine Levy, who is part of the campaign group End Our Pain, said many parents were “at their wits’ end” and struggling to afford prolonged and expensive treatment.

In an open letter delivered to the Prime Minister on Tuesday, the families demanded “urgent government assistance” in accessing medicinal cannabis.

Speaking outside Downing Street, Ms Levy, who lives in Mill Hill, said that treatment for her 26-year-old daughter Fallon had cost her £2,500 per month and that she had been forced to sell her home as a result.

“Since (Fallon) was five, she’s had no quality of life, she’s spent a lot of her time in a wheelchair in and out of hospital,” she told the PA news agency.

“Her life changed when she started using medicinal cannabis.

“I’ve sold my home personally; it’s cost me £2,500 a month to keep my daughter well.”

Ms Levy, who was joined by her husband Graham, said that they had become aware of a personal letter sent by Mr Johnson to the family of another epileptic child, congratulating them on having accessed treatment.

She said the Government should make treatment more available and not “cherry pick” individual cases.

“What about our children? What about all the other children that desperately need this medication?” she said.

“We need Boris Johnson to advocate for these families that have tried everything…to help our children with this debilitating, life-changing (condition).

“We can’t afford to pay any more and we’re at our wits’ end.

“You can’t cherry pick and decide that one family is OK to have it.

“It’s infuriating…in my opinion it’s always been about the money and the fact that they don’t want to pay for it.

“In another week’s time my daughter’s medication is going to run out.

“Where’s the prescription for my daughter and all the other families?”