The growing trend for big London firms to relocate support work to cheaper locations at home and abroad is gaining momentum, new research shows.

A report from commercial property consultancy CBRE coincided with news that magic circle firm Freshfields Bruckhaus Deringer is seeking office space in Manchester.

The firm, whose headquarters for 1,300 staff occupies 230,000 sq ft in Fleet Street, central London, has hired estate agent Knight Frank to look for 100,000 sq ft in Manchester city centre. It is being suggested that back-office staff will be moved, but other departments could follow later.

‘Northshoring’ legal support work to parts of the UK where office space is cheaper and wages lower has become a trend among the bigger firms. The annual rent for high-end office accommodation in Manchester, Glasgow or Birmingham is less than half that paid in London, while in Belfast it is under a third.

More than half of the biggest London firms surveyed by CBRE said outsourcing or moving certain functions, such as secretarial services, to other locations was either planned or in place. More than two-thirds expect to increase their London headcount over the next three years.

Frances Warner Lacey, senior director of the central London tenant advisory group at CBRE, said firms were looking at ways they could ‘squeeze more fee-earners into the same amount of space’. According to the CBRE report, the average area per fee-earner has fallen by 5% since 2012 to 490 sq ft in 2014. In that time, the average rental cost per fee-earner has increased 2% to £22,400 per annum.

Warner Lacey said Freshfields’ Manchester foray did not necessarily signify a mass exodus of its staff from London. ‘It’s important for law firms to be close to their clients,’ she stressed.

Freshfields declined to comment.