Professor Robin Shattock warned there is still no guarantee that its fast-track research will produce an inoculation with immunity against coronavirus.
But he said: “Assuming funding is there to purchase, we could have that vaccine rolled out across the UK in the first half of next year.”
Success or failure depended on the level of immunity that would be needed to protect against Covid-19, something which was “very difficult to predict”.
But the UK was in a “strong” position” with separate research at Oxford University, Professor Shattock said – and he hoped to “get an answer early next year”, he predicted.
Some 15 volunteers have been vaccinated for the trial so far, which will be ramped up to include another 200-300 participants in the “coming weeks”, the professor revealed.
Asked on Sky News if there was a chance that no vaccine being researched anywhere in the world would be successful, he replied: “I think that’s a very low, low risk.
“We’re very lucky in the UK that we have two very strong candidates, the one from Imperial, the one from Oxford, and so we’re pretty well placed – but there’s still not a certainty that either of those two will work.”
The comments come after Boris Johnson was accused of taking a risky gamble by refusing to join the EU-wide programme to secure a vaccine.
Ministers fear a cap on the number of doses allocated to each member state – and argue pharmaceutical companies are offering the UK similar prices to EU countries anyway.
However, the UK has refused to pay increased budget contributions to Brussels to do the work – and the opt-out could backfire if the EU secures a successful vaccine then denied to the UK.
However, the professor dismissed those concerns, saying: “I don’t think it matters at this stage because everybody is just working so fast, trying to move things so quickly, that success will come from many different avenues.”
He admitted some people would reject a vaccine, but argued the greater concern was having to push ahead at huge speed without the normal full trials.
“Normally, we would study a vaccine for two years before we made it widely available to the general public,” he said.
“And of course, we won’t have two years of safety for this vaccine or any of the vaccines that are being developed.
And, on the chances of success, he replied: “If you only need a very small amount of immunity, I suspect most of the vaccines that are being developed will actually work, but – if you need a very strong immune response or particular quality of immune response – we’ll see that actually it will be shaking out some of these candidates.
“We hope we will be the candidate, one of the candidates, that is successful, but there’s no certainty with any individual approach.”