Ministers are optimistic that COVID-19 vaccines will be offered to all 12 to 15-year-olds despite advisers failing to recommend it, Sky News understands.
The Joint Committee for Vaccination and Immunisation (JCVI) said on Friday that, while it would widen the programme to include more children in that age group with health conditions, it was not recommending the widespread vaccination of their healthy classmates.
However, sources say the government is keen to offer vaccinations to all children in that age group - and think parents would find it reassuring.
The UK's four chief medical officers, including England's Chris Whitty, have been asked to make a final recommendation - which should come within a week.
The Times reported that the vaccinations could begin as soon as next week.
Earlier on Friday, the JCVI had said that the coronavirus presents only a small risk to healthy children and, therefore, the benefit of being vaccinated was not great enough to support mass vaccination for this age group.
The independent medicines regulator, the Medicines and Healthcare products Regulatory Agency, has approved the Pfizer and Moderna vaccines for those aged 12 and over.
Efforts are already under way to recruit thousands of vaccinators for schools, and Education Secretary Gavin Williamson has previously said he "very much hopes" the under-16s could be vaccinated.
Last month, the vaccination programme was extended to all 16 and 17-year-olds - resulting in 1.4 million teenagers being offered a jab.
Professor Wei Shen Lim, chair of COVID-19 immunisation for the JCVI, said: "The JCVI's view is that overall, the health benefits from COVID-19 vaccination to healthy children aged 12 to 15 years are marginally greater than the potential harms.
"Taking a precautionary approach, this margin of benefit is considered too small to support universal COVID-19 vaccination for this age group at this time. The committee will continue to review safety data as they emerge."
Northern Ireland Health Minister Robin Swann said he agrees the issue of a wider rollout "warrants further consideration".
Health Secretary Sajid Javid said he was grateful for the "expert advice", adding that vaccines "have brought a wide range of benefits to the country, from saving lives and preventing hospitalisations, to helping stop infections and allowing children to return to school".
Wales's Health Minister Eluned Morgan said she had asked the country's chief medical officer to "provide guidance at the earliest opportunity on the clinical and wider health benefits of vaccinating this age group".
Scotland's Health Minister Humza Yousaf said he had asked for the review to be conducted "as soon as possible".
Speaking to Sky News, Professor Adam Finn, who is a member of the JCVI said "there is very little benefit" to vaccinating heath 12 to 15-year-olds against COVID.
When asked why the committee did not recommend a mass rollout of the jab for children in that age group, he said: "It's really about uncertainty.
"So we know that these vaccines work, they do prevent the disease but we also know that healthy children aged 12 to 15 very seldom get seriously ill with COVID and, in that situation, the fact that there are side effects, albeit very rare, which we don't really understand at this point, means that there is a risk that we could be doing more harm than good with the vaccine.
"In that situation, although it is not very likely, we really are cautious to advise that all children should receive the vaccine, it's really mostly to do with the fact that the risks of COVID in healthy children are so small."
He said the committee has been getting "very up to date" information from paediatric cardiologists in the US, who are managing children who have experienced myocarditis - inflammation of the heart muscle - as a side effect.
He added that although there were "small numbers" of children suffering with the side effect, there are still "some early concerns" that it might be a "problem in the longer term".
"We really do want to take care that we avoid a scenario, a theoretical scenario, where a vaccine programme is seen to be doing more harm than good," he said.
Prof Finn also noted that there has been a "lot of disruption to education for children, and really that is the biggest harm children have experienced during the course of this pandemic".
"The JCVI are not really experts in the area of education, how schools work, how staff and parents and children behave, and so in terms of how a vaccine programme or the consciousness of the availability of a vaccine programme might affect all that, we felt, if you like, out of our depth. That's something we can't really give expert advice on."
Geoff Barton, general secretary of the Association of School and College Leaders, said he is disappointed by the JCVI decision not to recommend jabs for all 12 to 15-year-olds.
He added that while they respect it, it could mean it is "more difficult during the autumn term and beyond to guard against educational disruption caused by transmission of the virus".
Vaccines minister Nadhim Zahawi will be a guest on Trevor Phillips on Sunday tomorrow from 8:30am