Seven people have died following multiple failures by a heart surgeon who continues to work for the NHS, the BBC has learned.

An NHS investigation found problems in Karen Booth’s cases included clinical errors, carrying out operations she wasn’t skilled or experienced enough to perform and not calling for help when she should have.

Serious concerns about Ms Booth’s performance at the Freeman Hospital in Newcastle were first raised by her colleagues in 2018 – but the hospital did not launch an investigation until 2021. Ms Booth is currently working as a mentor to other surgeons at the Freeman, which plans to allow her to resume her surgical career shortly.

Karen Booth “should never [again] practise as a surgeon”, said the family of one man who died after being operated on by her.

The Newcastle upon Tyne Hospitals NHS Foundation Trust, which runs the Freeman, did not respond to most of the questions put to it by the BBC, including why it thought it appropriate to let Ms Booth resume her surgical career.

The trust did however point to a problematic working culture in the cardiac unit at the time of the failures, while internal reports have criticised poor governance procedures and a reluctance from senior staff to take responsibility over safety concerns.

Ms Booth, a heart and transplant surgeon, did not respond to any of the BBC’s questions. The hospital told the BBC that the General Medical Council (GMC), the UK’s regulator for doctors, is investigating Ms Booth but there are currently no restrictions on her practice.

Concerns over Karen Booth’s record have been laid bare through emails and documents sent by her surgical colleagues – seen by the BBC – as well as reports the Freeman commissioned and the transcripts of meetings that senior clinicians from the hospital attended. All the information was passed to the BBC by families impacted by operations performed by Ms Booth.

Ian Philip, a construction worker from Blyth, Northumberland, died after an operation led by Karen Booth in March 2021 to try to repair problems with his heart valves.

Ms Booth had planned to carry out a complex type of heart operation called an Ozaki procedure, that very few surgeons in the UK are skilled enough to perform.

The surgery was approved by the hospital solely for use in children and young adults, the BBC understands, though Ms Booth had permission to offer the procedure for patients with aortic valve disease.

The procedure had not been discussed among the surgical team prior to the operation, according to the hospital’s communications with the family.

Once in surgery, Ms Booth and her colleague discovered a complication and decided against using the Ozaki procedure, instead choosing to repair a tear. A serious incident report found that this was “good practice” in the circumstances.

But further complications arose and the surgeons then failed to carry out a graft bypass, an operation the hospital later told his family was a “bread and butter” procedure that would have made Ian’s survival “much more likely”.

Mr Philip, described as a loving man by his family, was admitted to intensive care and placed on life support. He died six days later, aged 54.

Months later, an inquest was held into his death, but the coroner did not know that an internal investigation into Ms Booth was under way at the same time.

She gave evidence and told the coroner that she had done “the best I could”. The coroner went on to conclude that Mr Philip’s death was due to “an unusual and complex set of circumstances [which] conspired together,” and that Ms Booth “had an excellent CV”.

It would take over a year and a half for the hospital to let Mr Philip’s family know that the outcome could have been different, had a surgeon with the correct specialism been alongside Ms Booth in the operating theatre.

The Freeman did not respond to questions about how Ms Booth had come to be granted permission to use the Ozaki procedure, which she had used about 40 times in total. Internal analysis published by the hospital found that “there was no clear governance process for maintaining oversight of newly approved procedures”.

In late 2022, Mr Philip’s family were brought into the hospital and told they were one of eight families being contacted over failures by Ms Booth – seven in relation to patients that died, and one surviving patient who had experienced significant harm.

“The scale of what had gone on – we would never even begin to fathom what had happened,” Mr Philip’s son, Liam, told the BBC.

“We couldn’t process it at the time. We walked out of there bewildered.”

The Freeman’s investigation into Karen Booth had been ordered in May 2021 – two months after Mr Philip’s death – by Angus Vincent, a newly appointed associate medical director, after staff had approached him with their concerns about Ms Booth. The investigation looked into 22 of her cases, the BBC understands.

It found that a number of failures by Ms Booth had contributed to her poor outcomes. As well as surgical errors, she was found to have had poor insight into her own levels of competence, partly through being inexperienced, and that she had failed to seek help from more senior colleagues.

The investigation could not determine why Ms Booth had taken on such complicated cases, although it described her as “an enthusiastic surgeon with inadequate insight into her skills and experience.” Added to that, said the investigators, was likely to be the department’s complex caseload and an inadequate multi-disciplinary team (MDT) process – in which clinicians should come together prior to surgery to discuss the best options for patients.

A spokesperson for the Freeman would only confirm to the BBC that an investigation had taken place “focused on the practice of one consultant surgeon” and that eight patients “came to avoidable harm due to unexpected or unintended events during complex high-risk surgery”.

At the same time as the investigation into Karen Booth was taking place, a separate report into the culture of the cardiac unit by the Royal College of Surgeons (RCS), commissioned by the hospital, found bullying-type behaviours had been prevalent in the cardiac unit.

In a BBC interview about the RCS report in 2021, Mr Vincent – who was speaking on behalf of the hospital – said that “no patients had been harmed” due to the poor culture, despite by this time knowing of Ms Booth’s failures.

We asked the Freeman if the trust still stood by the remarks Mr Vincent had made – it didn’t respond.

At their meeting with Mr Philip’s family in 2022, the hospital said Ms Booth’s relationship with theatre staff was “excellent” and no concerns regarding bullying had been identified.

Astonished by what she had learned at the hospital meeting, Mr Philip’s widow, Melissa Cockburn, posted a message on social media asking other families who had been contacted by the Freeman to get in touch.

Instead, two members of staff from the hospital’s cardiac unit made contact and began to share a series of emails which showed Ms Booth’s colleagues had been trying to raise the alarm about her since 2018 – almost three years before Mr Philips had died.

One of the emails shared with Ms Cockburn included figures from a departmental mortality audit. These showed that in a unit of seven cardiac surgeons, eight of the 17 deaths between January and August 2018 had been Ms Booth’s patients.

The email had been sent to Andrew Welch – the Freeman’s medical director between 2013 and 2024 – and said: “These figures are clearly a worry.”

Another email to a separate clinical manager said: “There are worries from every single surgeon that she [Karen Booth] is taking on cases beyond her ability, expertise and experience,” citing “deaths and major complications”. The email said the surgeons nevertheless “all want to support her” and “make her a success”.

But the hospital failed to investigate, surgeons later claimed, or suspend her from practice.

Ms Cockburn told the BBC that “if these concerns had been listened to in 2018, a lot of people would still be alive today”.

Three years later, in 2021, the surgeons wrote to associate medical director Angus Vincent, sparking the investigation, saying they felt that “personal friendships and close associations had contributed significantly to the ignoring of concerns”.

The hospital did not respond when asked what steps it had taken to ensure the safety of patients during this time. Mr Welch, who now works for the trust in a different role, declined to comment to the BBC.

At one point, Ms Booth seemed to recognise her own failings, writing in an email to a colleague in September 2018 that “I have been far too brave and gone outside comfort zones in the last 6 months”, adding she had been told that “I need to develop broad shoulders but it certainly isn’t easy!”

In 2022, she highlighted the department’s poor working culture when questioned about Mr Philip’s death. She told the authors of the serious incident report into his death that she “felt unsupported by the rest of [her] colleagues and that support was sometimes difficult to muster”. The report found “significant tensions” in the cardiac unit meant there was no discussion of additional support from a more experienced surgeon.

After the internal Freeman investigation, Booth was reported to the GMC in 2022, which initially put restrictions on her practice, before lifting them in early 2024. The GMC would not comment on any aspect of its investigation.

Karen Booth is currently working at the Freeman in a non-surgical role, and has joined the hospital’s support programme as a mentor for surgeons who have been involved in adverse outcomes in surgery.

The hospital’s current medical director, Michael Wright, informed the cardiac team last November that Ms Booth was to resume her role as a heart surgeon, having undergone retraining at a London hospital.

In response, a collective email from a group of Ms Booth’s cardiac surgeon colleagues in June this year said the decision had “shattered trust in ways that cannot be repaired”.

“The focus on facilitating Ms Booth’s return has come at the expense of supporting those who raised concerns,” the email said.

Ian Philip’s family are now calling for an external investigation into all of Ms Booth’s cases, believing it may expose other cases of avoidable patient harm.

“There needs to be a comprehensive review of all the individual surgeon’s cases,” said the family’s lawyer, Nick Ward-Lowery from Hudgell Solicitors. “It is possible that there are further serious incidents which have not been acknowledged.”

The Freeman hospital says it is “currently considering” the next stage of Ms Booth’s phased return, “in line with appropriate standards, review recommendations and external advice”. It did not respond to questions as to whether it would be safe for patients if Ms Booth were to return to the cardiac unit, given the strong opposition from some of her colleagues.

In a statement, the Newcastle upon Tyne Hospitals NHS Foundation Trust, which runs the Freeman hospital, said the cardiac department “continues to be at or above the national average”.

“We have undertaken extensive work to address all of the issues raised, with updates regularly reported to the Trust Board, and we have made significant progress in addressing failings. Work remains ongoing to support the cardiac surgery department with further improvements.”