Professor Sir Chris Whitty has told a public inquiry he was "sceptical" about making Covid vaccines mandatory for healthcare workers.
The Chief Medical Officer for England told the Covid Inquiry the decision to implement the mandate was "100 per cent a political one".
Care home workers were mandated to be vaccinated against Covid-19 from November 2021 and were among the first to be given the jabs during the original rollout.
However, this scheme, known as vaccination as a condition of deployment (VCOD), was controversial. Proposals to widen the scheme to include all healthcare workers were later abandoned and the need for care home staff to be jabbed was lifted in 2022.
Prof Whitty said such a decision was a balance between the risk of having a vulnerable person cared for by someone who may pass on an infection to them and respecting a person's own autonomy.
"There's a range of opinions on this and for what it's worth - but I don't think it's worth very much - I'm rather more sceptical than some people that this is a good idea, but that's a view as a citizen," Prof Whitty told the inquiry.
He added that as a doctor he had several opinions on why mandatory vaccination had some advocates.
These include that it is already enshrined into law that a person who is a risk to others can not do certain jobs, such as a lorry driver with epilepsy; doctors already have a "medical responsibility" as outlined by the General Medical Council's guidance for doctors to protect patients from you giving them diseases, which explicitly includes vaccination; and historically some doctors with certain infections would not be able to do certain procedures.
Prof Whitty told the inquiry that the Covid mandatory jab ruling, therefore, was not novel but was still controversial.
"Every drug and vaccine has side effects, and some of those may be rare, but still severe, and that has to be taken into account in the decisions that are taken about mandation," he added.
"I was sometimes worried that people were just thinking, 'people should just get vaccinated. What's the problem?'
"And my view is that this is a medical procedure, and, more importantly, there will be side effects and they may well be rare around serious and that is an important part of the balance of risk."
Prof Whitty added that mandatory vaccination "has not got a very happy history" and pointed to the example of compulsory smallpox vaccination of children in 19th-century England, which led to a decline in vaccine uptake and the world's first "anti-vax" movement.
Prof Whitty said: "Smallpox is an example, and, in my view, what happened after mandation [of the coronavirus vaccine] in the social care system in England, I think probably will be added to that catalogue.
"But then the arguments on the other side are perfectly strong ones and if your own relative died from Covid and you knew that they caught you from someone who chose not to get vaccinated, I think you would have a strong view in the other direction.
"I accept, obviously, as a citizen, this is a balanced and difficult decision, but I just think it's important that the medical facts are in front of people, including the side effects, as part of that balance of decision."
Professor Dame Jenny Harries, CEO of the UK Health Security Agency (UKHSA) and a deputy Chief Medical Officer in the early phases of the coronavirus pandemic, also had reservations about mandatory vaccination, it emerged.
In an email sent on Feb 15, 2021, Dame Jenny said she was "quite outspoken" on the mandatory vaccination policy.
"I am hugely supportive of getting care homes protected, but I have seen no evidence to suggest that this policy is going to result in more benefit than harm," she wrote in the email, shown to the inquiry.
She added at the time that her own "gut feeling" was that this was a "hugely risky" endeavour as it could lead to "potential racial antagonism" because many carers in critical areas are from "minority ethnic backgrounds".
Speaking to the inquiry on Monday, she said she was "leaning away" from the mandatory vaccination policy at the time in her personal opinion.
"That was one of many views at the time and there were many good logical reasons, which I also understood, for why you would want to maximally protect a care home immediately," she added.