A homeowner was denied a new mortgage because he was hosting two Ukrainian refugees in an annex to the house.
Halifax, which initially rejected Dominik Zaum's application, reversed its decision and apologised after being contacted by a BBC consumer affairs programme.
Mr Zaum has hosted a mother and young daughter pair under the Homes for Ukraine scheme since June 2022. They are living in what he told the BBC was a "granny" flat attached to the main house.
When his fixed rate mortgage came up for renewal, he applied for one with Halifax but was rejected as the bank said there was a risk he might rent out the space in the future.
"We were very surprised by this because we've never rented it out, we're not renting it out now... and we have no intention of renting it out in the future," he told BBC's Money Box.
"When we contacted the Halifax through our broker they said they could not provide us with a mortgage because we were providing accommodation to a Ukrainian family and therefore there was a significant risk that we would rent out the room commercially in the future."
Halifax apologised for "the confusion" and offered a mortgage deal after being contacted by the Radio Four programme.
Under the scheme, just under 160,000 Ukrainians are living in homes across the UK. This includes 982, just over half a one percent, in Northern Ireland, according to the latest UK government figures.
