It depends how you define 'lockdown'. Technically, we're not in a lockdown now anyway (as, for example, non-essential shops are still trading, even in 'Tier 3' areas).
However this comes from an excellent article on Auntie Beeb's website:
"Suggestions that vaccines will be able to take us back to where we were pre-Covid by Easter next year have given people an unrealistic expectation, says Prof Salisbury, and such an outcome, in the absence of the interruption of transmission, is "unlikely".
Even countries with strong health infrastructure and experience of mass vaccination programmes - like the UK - will find reaching enough people to break the chain of transmission a challenge, he says.
While the outlook for at-risk groups will be "undoubtedly brighter" next year, Prof Salisbury says, the rest of us look likely to be taking extra measures for some time to come, something he refers to as "vaccine plus".
Prof Ghani agrees and estimates it will take two more years to "to get the whole world back to normal", but with the process likely to be quicker for high-income countries like the UK.
But she warns that while vaccines will ultimately end the pandemic, they will not "get rid of the virus" and the world will need to "keep vaccinating" just as it does with other diseases.
So with a new era of "vaccine plus" possibly now dawning in the battle against Covid-19, 2021 is likely to require us to continue to dig deep for a number of months to come - and possibly beyond."
https://www.bbc.co.uk/news/resources/idt-b6360f40-84f9-469b-b6a3-a4568e161c4f