The brokerage firm raised its ratings on Land Securities and British Land to "neutral" from "sell" while arguing that the ongoing shift to hybrid work models could take a while.

"In London, the drive to return to the office is taking much longer than expected, as are corporate decisions on long-term space requirements," Citigroup analyst Aaron Guy said.

But, remote work could still push desk occupancy in many offices below 50% over the medium term, causing a fall in demand and rents, Guy cautioned.

Commercial landlords have already suffered steep declines in rental income and footfall at retail spaces due to the COVID-19 pandemic.

As businesses adjust to flexible models of working, they may not give up existing spaces until new office designs become certain, flexible technology is tested and new space is found or existing space is refurbished, Guy said. "This process could take years."

There still remain risks that could push demand for office spaces lower by about 40% and office rents by 30%, Guy said while noting that any such possibility would be delayed.

(Reporting by Tapanjana Rudra in Bengaluru; Editing by Sachin Ravikumar and Uttaresh.V)