The firm, Stephenson Harwood, said it would allow staff to work remotely but pay them 20% less than their current salary.
Since the start of the pandemic a debate has raged over who gains and who loses when staff work from home.
Employees save time and money, but employers can save too, on office space and costs.
Some argue workers are less productive when unsupervised at home. Others say without the commute they work longer hours, often spilling over into evenings and weekends and face fewer distractions.
Most recently cabinet office minister Jacob Rees-Mogg sparked controversy when he said all civil servants must stop working from home. and left notes on empty desks saying "I look forward to seeing you in the office very soon."
Academic studies suggest remote working can boost productivity. And many private sector firms have found that hybrid working, allowing a combination of home and office work, frees up space and improves staff satisfaction.
Stephenson Harwood told the BBC that it had recruited some remote workers from outside London during the pandemic, on a lower pay package, reflecting the lower cost of not commuting into the capital.
But if they do need to go to the office remote workers could claim travel expenses, he said.
The firm is now extending the remote working option to existing staff, but also applying the salary difference between the two packages, the firm said.
The choice of full-time remote working is available to all employees but not to partners in the firm.
Stephenson Harwood said it didn't expect many people to take up the offer to work remotely full-time.
A newly qualified lawyer, for example, starts on a salary of £90,000, at the law firm. But the chance of them choosing to take £72,000 instead to work from home were "very slim" as their role required experience of the office environment, he said.
The spokesman said the firm's current policy, where people can choose to work from home for up to two days a week, suited many of its 1,100 employees across offices in London, Paris, Greece, Hong Kong, Singapore and South Korea.
"For the vast majority of our people, our hybrid working policy works well," he told law firm news website RollOnFriday which first reported the story.
Stanford University academic Nicholas Bloom estimates that post-pandemic about 10% of employees will work fully remotely.
He argues that homeworking could boost productivity, narrow regional inequalities and help blue-collar workers win more flexibility.
However, some firms are encountering resistance to a return to the office, even on a hybrid basis.
A handful of Apple staff have reportedly told boss Tim Cook his plan for them to work from the office three days a week will make the company "younger, whiter and more male-dominated".
In an open letter they said a compulsory return to the office "will change the makeup of our workforce" and "lead to privileges deciding who can work for Apple, not who'd be the best fit."
It said the office would be made up of staff who lived nearby, young people without family commitments and parents who had a stay-at-home partner.
The letter has around 200 signatures, just 0.1% of the firm's 165,000 staff.
It came in response to an email from Mr Cook which said returning to the office was "a positive sign that we can engage more fully with the colleagues who play such an important role in our lives".
Mr Cook said he was "deeply committed" to giving his staff support and flexibility.