The death of Nicholas Geldard still strikes fear into the hearts of children's specialists – and will be on the minds of ministers and chief medical officers as the UK prepares for what is likely to be its worst winter flu season for a generation.

In December 1995, 10-year old Nicholas, who had suffered a brain haemorrhage, was shunted between four hospitals in the north-west in a frantic search for an intensive care bed. His parents had to follow his ambulance across the Pennines in a blizzard before being told he was clinically dead.

Nicholas's death provoked an outcry (Harriet Harman, then MP for Peckham, said it was "hard to find words to express the sense of outrage and betrayal that everyone must feel") and was the catalyst for reform of how critically ill children were treated in the NHS. In the past decade, the number of intensive care beds for children has more than doubled to 600 and hospitals have 24-hour retrieval teams on standby to find the beds for the children who need them.

Yet paediatric intensive care remains one of the most high-pressure services in the NHS – and the most vulnerable to being overwhelmed by swine flu. The nightmare for doctors, ministers and health officials this winter would be a repeat of the Nicholas Geldard tragedy many times over.

NHS trusts have been preparing for a flu pandemic for three years, alerted by the Asian avian flu outbreak. Swine flu has surprised them because while it is mostly mild, it is targetting children. Last week, 169 children aged under five were hospitalised with the virus, a rate five times that for older age groups; 12 were in critical care.

In summer, this is manageable. Few other viruses are about and swine flu is the only show in town. But in winter, if flu is raging on top of other respiratory viruses that tend to keep intensive care units full – Respiratory Synctial Virus is the main culprit, along with noroviruses and adenoviruses – the situation may look very different.

Sir Liam Donaldson, England's chief medical officer, sought to reassure the public yesterday, promising extra capacity could be found, if necessary by cancelling routine operations (about half of paediatric intensive care beds are taken by children recovering from heart operations and the like).

The message from the consultants who run the units is gloomier. They experienced "huge" pressure over the past two winters and they view this coming one with trepidation. Many units have asked for more beds – few have been granted them, and if they were, they would still face the problem of staffing and equipping them. Intensive care nurses are highly skilled and hard to find and the range of equipment needed is enormous – ventilators must fit premature babies through to strapping teenagers.

The challenge is huge. The virus is targetting children and causing more severe illness in them than in others. How the paediatric intensive care service copes could turn out to be a touch stone for the handling of this pandemic.