Bob Weighton, from Alton, Hampshire, only took up the title of the oldest man in the world last month after the previous holder, Japanese man Chitetsu Watanabe, died aged 112.
Last year, the former teacher and engineer celebrated his 111th birthday with his many friends but this year the supercentenarian - aged 110 or over - will be alone due to the coronavirus lockdown.
"Everything is cancelled, no visitors, no celebration," he said.
"It's a dead loss as far as celebration is concerned."
The coronavirus pandemic is said to be the worst outbreak since then, although Mr Weighton said he does not remember it as nobody he knew had it and children do not read newspapers.
He said the "world is in a bit of a mess" at the moment and is concerned because "nobody knows what is going to happen".
"In the Second World War you knew what you had to do, you might fail but the objectives were clear as Churchill rallied the country behind him, 'We will fight on the beaches', etc etc," he said.
"We knew exactly what we had to do.
"That was an objective that you could possibly reach, but nobody knows how we are going to defeat the virus."
The father-of-three, who has 25 great grandchildren, said being in self-isolation has meant he has become more dependent on the Brendoncare home where he lives, especially for meals and from his assistant.
"It means that I have to be more self-sufficient, do my own cooking, cleaning, read the books that I haven't read.
"I am less capable of doing things for myself than I was 10 years ago - I can't lift the weights, I can't move as fast, I can't even dress myself properly.
"I depend very much on other people these days."
When it comes to the secret to longevity, Mr Weighton said there is not one.
He said: "I never intended to be this old. When you are young, you don't think about what is going to happen when you're old, you're self-engaged, all you think about is the here and now."
Mr Weighton said he reads a lot and constructs model windmills to keep himself active and young.
He also turned down the traditional birthday greeting from the Queen because he has "had about 10" already.
"I don't see why I should require the Queen to keep giving me cards," he said.
"It costs the taxpayer not her something, so I have selected one in which she is smiling, looking happy and contented and that's the one I like and I keep that."
Mr Weighton happens to be born on the same day as Britain's oldest woman, Joan Hocquard, from Poole, Dorset, and although he does not know her said he would like to "send her my best wishes".
