Conjoined twin Faith Williams, who was born four weeks ago, has died.
Faith survived surgery to separate her from twin sister Hope but died yesterday “from the complexities of her condition”, said a spokesman for Great Ormond Street Hospital.
He added: “She required the full range of skills of our intensive care staff, and underwent a number of further procedures.
“However, she succumbed to the complexities of her condition.”
The twins were born on November 26. Hope died following surgery to separate them at the beginning of the month.
They were joined from the breastbone to the top of the navel and had a shared liver but separate hearts.
Their parents Aled, 28 and mother Laura Williams, 18, from Shrewsbury, Shropshire, maintained a constant vigil at their bedside.
Faith underwent surgery earlier this month to assist with her circulation.
A spokeswoman for the hospital said: “The aim was to ensure more blood flows to her body and less through her lungs.”
Following the heart surgery the baby had another operation to close her chest.
“While this is a sad outcome, it is not an unexpected one,” the hospital spokesman added.
Hope failed to survive the initial operation to separate her from Faith because her lungs were too small to support her breathing.
Mrs Williams is Britain’s youngest mother to give birth to conjoined twins.
The hospital spokesman added: “Mr and Mrs Williams have asked us to say that they were very happy with the care they and their children received at Great Ormond Street.”