A six-year-old boy who suffered a catastrophic brain injury after contracting the herpes simplex virus has won a record £37 million in compensation from the NHS.

The High Court heard that following his birth at Watford General Hospital, the youngster caught the disease, which developed into a devastating brain fever.

The boy's barrister, Henry Witcomb QC, told the court that the infection "should have been but was not" detected and acted upon soon enough.

The two-day delay before he was treated resulted in "catastrophic" brain damage.

The boy, who cannot be identified, suffers from eyesight and communication problems, cognitive and movement difficulties as well as behavioural issues.

His lawyers sued West Hertfordshire Hospitals NHS Trust, which runs the hospital, for damages.

Mrs Justice Lambert said the late diagnosis meant a delay in giving him anti-viral medication.

She added: "The effects of the negligence have been tragic both for the boy and his family."

She said that the trust admitted liability at an early stage and had agreed to settle his case.

The boy will receive a lump sum payout, plus annual payments to cover the cost of the 24-hour care he will need for life.

The total value has been calculated to be more than £37 million.

John Whitting QC, for the trust, said its chief executive wrote to the boy's family to apologise in May last year.

He added, on behalf of the trust: "The care which he received was not of an appropriate standard and for that we are acutely sorry."

The judge praised the "quite astonishing" care and devotion shown by both parents to the boy, at "very considerable" cost to their own physical and mental health.

"I am pleased to approve the order," added the judge, who wished the family "the very best for the future".

The boy's solicitor, Paul McNeil, of law firm Fieldfisher, said after the hearing: "We are grateful to the courts for approving a settlement in this long-running, catastrophic child injury case that has devastated the family.

"The settlement will ultimately enable the family to access funds to pay for vital care, education and therapies for life.

"While we recognise that this is the highest award ever made against the NHS, our hope is that such accidents will never be allowed to happen ever again in the future."