The fantastic news was given to her parents just 28 days after her bone marrow transplant, following a successful nationwide appeal for a donor.
Her parents Yaser and Vicki, who is originally from Essington, were expecting an anxious eight-week wait to find out the result of the transplant.
But in just half that time they can look forward to the results of one more bone-marrow test this week to confirm that she is leukaemia free.
Today her father spoke of the great relief he and Vicki had experienced after receiving the best possible results from a scheduled blood test last week.
"We knew the blood test was scheduled but it was an unexpected and wonderful surprise to get such positive news," he said.
"The doctor told us that of all the possible results, this was the best outcome we could have had.
"It's a real mix of emotions for us right now but we are thrilled at this news.
"We are in a ward with many others who have been here a lot longer than us.
"The doctors call it 'disease free survival' so hopefully we are along that road now."
Yaser said doctors at Great Ormond Street Hospital in London had taken a sample of Margot's bone marrow on Friday for further examinations.
"This is the definitive test to see whether or not she is disease free.
"But even then it doesn't mean she is cured by any means.
"We are part way down a long road and we will continue to take each day at a time."
That road will involve weaning little Margot off her intravenous drugs as well as her drip food.
The 18-month old is currently recuperating in hospital after undergoing a bone marrow transplant last month.
"The next stage is to try and get her off the intravenous drugs and start her recovery from this blitz of drugs into her system," said Yaser.
"Our hope is that she can recover from that and move on to oral drugs, as well as getting her onto normal food.
"Then we can start to think about getting her home, but that is likely to be a few weeks away yet. "