A number of companies say they will not take on new staff who refuse to have the Covid-19 vaccination on non-medical grounds.

The moves comes after the vaccines minister Nadhim Zahawi told BBC News on Tuesday: “It’s up to businesses what they do, but we don’t yet have the evidence of the effect of vaccines on transmission.”

Fellow MP justice secretary Robert Buckland says that although it was unlikely firms could legally require workers to receive a jab to keep their current job, employers may be able to draw up contracts requiring new staff are vaccinated against coronavirus.

Pimlico Plumbers has already announced that it won’t take on new staff that aren’t vaccinated without a medical reason. Owner Charlie Mullins plans to make the jab mandatory for all new hires.

Mullins said: “We’ve obviously been talking to our lawyers and they’re very happy that we can add this proposal to any new workers that start with us once the vaccine is rolled out.”

Care home group Barchester Healthcare has also said it will not take on new staff who refuse to have the Covid-19 injection on non-medical grounds.

However, there are concerns about whether a requirement to be vaccinated could lead to discrimination against people who are unable to, or choose not to receive, a vaccine.

Prime minister Boris Johnson has played down the idea of ‘vaccine passports’, suggesting he wants to focus on mass vaccination and the availability of rapid testing, rather than making it necessary for people to have a Covid-19 jab in order to access jobs or go to certain places.

Law experts generally say that only hiring vaccinated workers is legally risky, with companies potentially being accused of discrimination.

Ben Stepney, employment lawyer at Thomson Snell & Passmore, said: “The legal risks associated with imposing a requirement on new recruits to have received their Covid-19 vaccination, as opposed to existing employees, may be less, but still needs serious consideration. The primary concern is of indirect discrimination claims on the basis that the requirement to have received the vaccine could put those of a certain race, religion or with certain disabilities to an unfair disadvantage.

“Employers can justify indirect discrimination where they can show it is a proportionate means of achieving a legitimate aim, such as protecting the health and safety of the working environment and colleagues they work with. It would be key therefore for employers to have thought through exactly why they wish to require new recruits to have received the vaccination and whether there are proportionately less intrusive means of achieving the same aim.”

“Employers are likely to be on stronger ground in justifying vaccination where the workplace does not make social distancing easy, for example care homes, and with reference to the primacy of health and safety of staff, customers, visitors and service users (as applicable).”

Marcus Difelice, employment law partner at JMW Solicitors, said: “A ‘Covid-vaccinated only’ hiring rule is likely to be high risk legally for any business considering making that move, regardless of sector or industry.

“Businesses may be able to justify the policy – even if discriminatory – but it’s a high bar and very challenging legally. Companies considering a ‘jab for jobs’ rule really need to consider their reasoning carefully, and make sure that is completely clear, before applying such a policy.”