A couple from north London may have to sell their home to pay for pioneering cancer treatment for their son.
Jack is due to start the treatment any day
Yvonne and Richard Brown, both Metropolitan Police officers, have flown their family to New York, US, so Jack, aged five, can be treated.
But they are £375,000 short of the £750,000 needed to treat Jack, who has neuroblastoma which attacks the nerves.
Mr Brown said: "We are determined to keep going... to make sure he has the best possible chance."
In the last two years Jack has spent 300 days in hospital undergoing chemotherapy and radiotherapy.
When a tumour appeared on his brain in November his parents, who live in Brent, were told there was nothing that could be done for him in the UK.
It was then they turned to the Memorial Sloan-Kettering Cancer Center in New York.
His mother Yvonne explained: "They have developed an anti-body which is capable of carrying liquid radiation directly to the cancer cells that remain in his brain.
"They are the only place in the world that offers this and they have had a 100% success rate with it."
Mr and Mrs Brown's work colleagues have helped raise hundreds of thousands of pounds for the treatment and now police in New York and Florida have pledged money.
Jack is due to start the treatment in the next few days.