Dr Isyaka Mamman, 85, had been suspended by medical watchdogs for lying about his age and sacked but then re-employed by Royal Oldham Hospital before the death of Shahida Parveen.

He had been responsible for a series of critical incidents before the fatal procedure in 2018.

Mamman will be sentenced on Tuesday after pleading guilty to gross negligence manslaughter.

He was told by the judge to "prepare" himself to spend time in jail.

Ms Parveen, 48, went to the hospital with her husband, Khizar Mahmood, for investigations into possible myeloproliferative disorder in September 2018, Manchester Crown Court was told.

She was advised to have a bone marrow biopsy, which was allocated to Mamman.

He failed to obtain a sample during his first attempt and instead performed a "highly dangerous" procedure, despite objections from the patient and her husband.

The method required him to take a sample from Ms Parveen's sternum but, after using the wrong needle, he missed the bone and pierced her pericardium, the sac containing the heart.

As a result, he caused massive internal bleeding.

Ms Parveen lost consciousness as soon as the needle was inserted, causing her husband to flee the room shouting: "He killed her. I told him to stop three times and he did not listen."

The crash team arrived but Ms Parveen was confirmed dead later that day.

'True age' is a matter of 'controversy'

The Nigerian-born doctor had used various dates of birth and left his previous job through "poor performance".

Mamman, of Royton, Oldham, qualified as a doctor in Nigeria in 1965 and had worked in the UK since 1991, the court was told.

From 2004 until Ms Parveen's death, he was employed by the Pennine Acute Hospitals NHS Trust.

However, his "true age" is a matter of "controversy", the court heard, as his birthplace had no birth registration system.

Throughout his professional working life, he gave a number of different birth dates.

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During his medical training, he gave a date of 16 September 1936, which meant that he was 21 when he began his medical training and 81 at the time of the fatal incident.

He later told the NHS his birth year was 1941, suggesting he began his medical degree at 16.

As it was approaching his time to retire, he changed his date of birth again, this time claiming it was October 1947.

The date, which would imply he started his degree at the age of 10, was used on his application for naturalisation as a British citizen in 2001.

Three years later, he was found guilty of serious professional misconduct by the General Medical Council and suspended for 12 months for lying about his age.

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'Grotesque catalogue of failings'

Complaints had also been made against him in the past, with one patient saying he used "excessive force" during a bone marrow biopsy in 2015.

Despite the patient being assured he would only be able to carry out "light duties" as a result of the complaint, there was another clinical incident in the same year, which resulted in serious injury to another patient.

Again, this was caused during a bone marrow biopsy and involved a needle being inserted in the wrong place.

The patient survived but has been left permanently disabled.

One lawyer said it was clear Mamman was a "failing" doctor but "should not have been allowed to be in the position he was", describing the choice as a "grotesque catalogue of failings" by the hospital trust.