The government is "confident" of increasing the supply of COVID vaccines in the coming months to allow the UK to "increase the pace" of its rollout programme, a cabinet minister has told Sky News.
Housing Secretary Robert Jenrick promised the UK would remain as one of the fastest countries in the world to vaccinate its population.
Despite a recent vaccine export row with the EU - and supply problems from India - Mr Jenrick stressed the government was "on course" to meet its target of offering a first dose to the top nine priority groups by 15 April and all UK adults by the end of July.
"We've built an infrastructure in this country that really is world class, it would enable us to vaccinate even more people than we have done in recent weeks - millions more people," he said.
"So the more vaccines we can secure, the more jabs can go into people's arms. But we do have enough supply in sight to continue to meet our obligations.
"That means if you have an appointment for your second jab, you should not be worried, that will be honoured, you will get that jab on the date you're provided."
The UK has so far given a first vaccine dose to nearly 29 million people, which is 55% of the adult population.
And, raising the prospect of the UK's vaccine rollout operating even faster if supplies are boosted, Mr Jenrick added: "We'll continue to be one, if not the leading, country in the world for the vaccine rollout.
"But if we can secure more supply - and we're confident that we will do, incidentally - in the months ahead, then we can continue to increase the pace, which is critical.
"Because the vaccine at the end of the day is our route out of this situation."
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After weeks of wrangling over vaccine supplies, the UK and EU have vowed to work together to create a "win-win situation and expand vaccine supply for all our citizens".
But tensions remain over Brussels' introduction of export controls on vaccines produced within the bloc, as EU leaders seek to respond to criticism over their sluggish rollout of jabs.
European Commission President Ursula von der Leyen used a European Council summit on Thursday to warn vaccine manufacturer AstraZeneca that it must "catch up" on vaccine deliveries for the EU before it is allowed to export jabs to other countries.
Mr Jenrick said it was "unhelpful" to talk about the possibility of the UK banning vaccine exports to the EU in retaliatory action.
But he said the government would "continue to discuss the situation with the EU to encourage them to stick to the very clear commitments that they gave just a few weeks ago, which were that existing contractual obligations will be honoured, that vaccines and other medicines can cross borders unhindered".
He also praised AstraZeneca as "fantastic" and said the company and other vaccine manufacturers "deserve our support in light of all that they're doing to produce vaccines, protect us from the virus and help us move forward".
The UK had been singled out by Ms Von der Leyen for failing to export any vaccine doses.
Asked if that was correct, Mr Jenrick said vaccines were "based on complicated international supply chains" with elements of jabs produced in the UK, EU and all over the world.
"It is critical for all countries that there are free-flow of medical products, including vaccines, across international borders and it would be very damaging if countries started to pull up drawbridges and prevent vaccines, medicines, or elements of them crossing international borders," he added.
"The UK strongly, strongly opposes that."
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