Over a 12-month killing spree Lucy Letby murdered seven babies and attempted to murder seven others - making her the most prolific baby killer in modern British history.

Her crimes put her close to the top of the list of notorious serial killers – ahead of Moors murderers Ian Brady and Myra Hindley, who killed five children in Manchester in the early 1960s; nurse Beverley Allitt, who killed four of her child patients in 1991, and Robert Black, who raped and murdered four young girls in the early 1980s.

She also becomes the second worst female serial killer of all time behind Rose West, who is serving a whole life tariff for the murders of 10 young girls, including her eight-year-old step-daughter.

Amelia Dyer, a Victorian baby farmer, is estimated to have killed 400 infants over a 30 year period. However, she was only ever found guilty of one murder.

The UK's worst ever serial killer was Dr Harold Shipman, who used his position as a family GP to murder an estimated 250 patients.

Letby murdered seven babies. Myra Hindley (left) helped her partner Ian Brady kill five children. Fellow nurse Beverley Allitt (right) killed four of her child patients in 1991

Dr Harold Shipman used his position as a family GP to murder an estimated 250 patients, while Robert Black raped and murdered four young girls in the early 1980s

Hindley and Brady's first murder came in July 1963 when they slaughtered 16-year-old Pauline Reade after persuading her to get in their car.

They went on to abduct and kill four more children before burying their bodies on Saddleworth Moor. Keith Bennett, 12, is the only victim whose remains have not yet been found.

The couple were jailed for three murders in 1966. They later confessed to another two murders before Hindley died aged 60 in prison in 2002. Brady died in 2017.

Beverley Allitt - known as the 'Angel of Death - killed four babies and poisoned nine others over 59 days at the Grantham and Kesteven Hospital in Lincolnshire, in 1991.

Originally, Allitt's crimes were suspected to be down to natural causes, but blood samples retained from nine of the children who had collapsed or died revealed that they had been injected with lethal doses of insulin, potassium or lignocaine.

She was handed 13 life sentences and ordered to serve a minimum of 30 years behind bars after a court trial in 1993.

The 54-year-old is currently receiving treatment at Rampton Secure Hospital in Nottinghamshire, and is eligible for parole.

Robert Black was handed 12 life sentences for murdering four girls aged between five and 11 in the 1980s but is suspected of being responsible for countless more.

He spent the the 1970s and 1980s working as a delivery driver and cruised the length of the UK looking for young victims to abduct.

His reign of terror ended in 1990 when he was caught by police with a barely alive six-year-old girl.

She was found hooded, bound, gagged and stuffed in a sleeping bag in the back of his van in the Scottish village of Stow.

Letby is the second worst female serial killer after Rose West, who - with her husband Fred - abducted, tortured and raped 12 women over a 20 year period at their house in Cromwell Street, Gloucestershire.

Fred, who confessed the killings, committed suicide in his cell while on remand at HMP Birmingham on New Year's Day, 1995, while Rose remains in prison.

Britain's worst ever serial killer was Dr Shipman, who killed an estimated total of 250 patients over a 27-year period stretching back to 1971, using the drug Diamorphine.

Around 80 percent of his victims were elderly women with his youngest victim a 41-year-old man.

Nurse Lucy Letby's crimes are among the worst ever seen in Britain

Amelia Dyer, a Victorian baby farmer, murdered infants in her care over a thirty-year period and is estimated to have had hundreds of victims - but she was only ever found guilty of one infant

Shipman was convicted of drug offences in 1976 after becoming addicted to pethidine as a young doctor, but he was allowed to carry on practising by the General Medical Council (GMC).

Victims 'cried in ways staff had never heard' Lucy Letby inflicted such pain on some of her tiny victims that they cried unnaturally - and even screamed - in ways staff on the unit had never witnessed. One little boy screamed both from the killer's unseen blow to his liver and the effects of her pumping air into his system. Medics on the unit could do nothing to comfort him as he continued crying for half an hour. Dr Sandie Bohin, one of two paediatric experts called in by the prosecution, said in evidence that the episode was 'most unusual'. She added: 'I have never observed a neonate to scream'. Advertisement

He began his killing spree in Pontefract General in the early seventies, and was eventually arrested in September 1998 aged 52, and was jailed for life in January 2000.

Letby murdered five boys and two girls between June 2015 and June 2016.

She targeted one set of triplets and three sets of twins and her victims ranged from a full term baby girl to infants born extremely prematurely, including one baby girl who survived despite being born in a hospital toilet at just 23 weeks gestation.

It is unlikely that the identities of any of the babies will ever be made public.

All were made the subject of life-long anonymity orders by the judge before the trial began, banning the media from naming them or their parents.

On one occasion it was claimed Letby murdered a tiny, ten-week premature baby boy because she was angry that one of her friends she was texting did not understand why she was upset at being given a break from working in intensive care following the death of another baby.

Criminologist Professor David Wilson told the Mail that this desperation to be acknowledged at work were signs of a 'hero complex,' and narcissism in Letby's personality.

Placing herself at the centre of a crisis was also indicative of the mental condition, Munchausen's, he said.

A corridor within the Countess of Chester Hospital's neonatal unit, where Letby worked

'She sees herself as deserving of attention and with skills that are superior to other people,' he said. 'She sees herself as a saviour - she has unique skills no other person can possess.

'But she is quite unusual to other health care and nurse serial killers, who are often seen as odd by their peers, because she did have friends and people she socialised with.

'The other thing is she is creating a crisis around her, which is a form of Munchausen's. Extraordinary stories are being told about what happens when she is on shift. She's saying, 'look at all the things that occur when I'm around.' It's also a ruse to get the doctor that she fancies there.'

After being convicted by a jury, Letby now likely faces a full life tariff.

Undated handout photo issued by Cheshire Constabulary of a cot where a baby referred to as Child G in the Lucy Letby court case. The black circles were added by the police

There are around 60 criminals still alive who are serving whole life orders, according to government figures.

They include Met PC Wayne Couzens, who kidnapped, raped and murdered Sarah Everard; Milly Dowler's killer Levi Bellfield; and Michael Adebolajo, one of Fusilier Lee Rigby's killers.

Other notorious lifers are Mark Bridger, who abducted and murdered five-year-old April Jones in Powys, Wales, in 2012; neo-Nazi Thomas Mair, who killed MP Jo Cox; Grindr serial killer Stephen Port; and terrorist Khairi Saadallah - who murdered three men in a park in Reading.