Lucy Letby is said to have tried to kill a twin baby boy, Child F, by poisoning him with insulin a day after murdering his brother (Pictures: Julia Quenzler/Chester Standard/SWNS)

Nurse Lucy Letby would have needed a ‘Nostradamus-like ability’ to have known when and how to kill one of her infant victims, her barrister has told jurors. 

The 33-year-old denies murdering seven babies and attempting to murder 10 others at the Countess of Chester Hospital between June 2015 and June 2016. 

She is said to have tried to kill a twin baby boy, Child F, by poisoning him with insulin a day after murdering his brother. 

Manchester Crown Court has heard Letby contaminated two bags of nutritional feed given to him intravenously. 

She is accused of injecting it into the first bag of total parenteral nutrition (TPN) during a night shift in the early hours of August 5, 2015, which caused Child F’s blood sugar levels to plummet. 

The neonatal nurse is then said to have ‘cynically covered her tracks’ by contaminating a second stock maintenance bag to be used by an unsuspecting colleague after she clocked off. 

Jurors have been told a blood sample taken when the second bag was in use later revealed a ‘biological fingerprint’ which showed synthetic insulin was present – when none was prescribed. 

But as he continued his closing speech, Letby’s KC Ben Myers said: ‘There is no evidence that Miss Letby interfered with any bag of TPN. None.  

‘Blink, ladies and gentlemen, and you will miss that point. We say there would be nothing quick about what the prosecution alleges.  

Letby denies murdering seven babies and attempting to murder 10 others (Picture: Chester Standard/SWNS)

Court artist’s sketch of Letby in the dock (Picture: Julia Quenzler/SWNS)

‘It involves getting a syringe and the bag, drawing up the insulin and injecting it without arising suspicion and getting caught. 

‘The prosecution has suggested alternatively that the insulin was introduced when the bag was hanging.  

‘It still involves getting insulin from the fridge, having a syringe, getting it in the bag without detection when there is no reason for anyone to put insulin into a hanging TPN bag. 

‘It’s quite easy to make the allegations but it would be quite difficult to carry out.’ 

Letby did not have exclusive access to the TPN bags, Mr Myers said. 

He told jurors the evidence was that the overnight TPN bag – which lasts up to 48 hours – had to be replaced at noon later that day when Child F’s cannula came out. 

The barrister added: ‘We say it’s incredible to maintain she is responsible for this. How can Ms Letby be held responsible for that second bag on any fair or logical basis?  

‘A high level of insulin in a bag that no-one could have foreseen would have been used which comes into play hours after she has left.’ 

Court artist’s sketch of Benjamin Myers KC from the Lucy Letby trial (Picture: Julia Quenzler/SWNS)

He said the evidence indicated there were five stock maintenance bags at the time in the neonatal unit’s fridge. 

Mr Myers said: ‘So even if somebody guessed that a maintenance bag may be needed in an unexpected way, they are not to know what bag would be taken.  

‘They would have to do the lot to make sure. You will keep in mind that stock bags are not stored in any particular order. It’s like a series of Russian dolls of improbability. 

‘There is no evidence that any other baby was affected at this time, and you can be sure we would be told if there was. 

‘How on Earth is this a targeted attack unless Ms Letby had a Nostradamus-like ability to read the future? This is completely unrealistic. 

‘This is not party games – let’s get Letby. We are not here to invent explanations and ignore the evidence.