Charlotte was born with brain, lung and kidney damage

Darren and Debbie Wyatt said they were "disappointed" by the judgement but welcomed the judge's recognition that Charlotte's condition had improved.

The couple, from Portsmouth, will now take their 18-month-old daughter's case to the Court of Appeal.

The High Court upheld a ruling allowing doctors not to resuscitate Charlotte.

Only today we heard from the trust that she had put on significant amounts of weight over the last four weeks Charlotte's parents' solicitor

In a statement on their behalf, solicitor Richard Stein said: "Darren and Debbie are very disappointed that the judge has confirmed that as things stand, Charlotte will not be ventilated in the event she requires it.

"He did, however, recognise that her condition has changed significantly - in fact, it continues to improve.

"For example, only five weeks ago, there was evidence before the judge that she was badly malnourished and only today we heard from the trust that she had put on significant amounts of weight over the last four weeks."

However Charlotte's grandmother Mrs Julie Wyatt, from Tamworth, Staffordshire, said she did not think doctors should resuscitate her granddaughter if she stopped breathing.

She told BBC News: "I don't think she would ever be able to walk or maybe even eat properly on her own even though she is being spoon-fed at the moment, just tiny bits.

Subject to review

"I don't think she would grow up to be a perfectly healthy child. I think she would be a lot of work for the parents.

"Myself, I'm trusting the hospital decision at the moment because I've seen the care they've given her and I know they love her, they've been with her 17 months of her life and I think they love her and they don't want nothing to happen to her.

"They are not withholding any treatment at all and I do believe that if they don't resuscitate her, it is for Charlotte's best interests, to be quite honest."

Mr Justice Hedley said that the new order was open-ended and remained subject to review.

Doctors said Charlotte has "no feelings other than continuing pain", and earlier the court had heard how experts believed her life was "intolerable".

But the Wyatts believe Charlotte is improving.

She was born three months premature at St Mary's Hospital, Portsmouth, in October 2003, with serious brain, lung and kidney damage.

In October last year doctors at the hospital won the legal right not to resuscitate her.