CMS has for the first time unveiled details of its new City offices, which will operate with no landline telephones, as the firm prepares to move early next year.

The firm has secured a six year rent-free lease for 78 Cannon Street, which will hold all CMS staff currently in London, including those from legacy Dundas & Wilson's London office who completed their move into the firm's current base at Mitre House in May.

The Cannon Street office will be 130,000 square feet, 30% smaller than seven-floor Mitre House, but will hold 10% more staff.

The new three floor, open plan office will be designed to have dedicated areas for each team and practice sector.

"This is a really strong way to bring strength to our sector group strategy," said CMS managing partner Duncan Weston. "It's all designed around our clients and our sector groups. This is a first for the legal industry."

Rents at the new building will be "similar" to Mitre House, according to Weston. "Commercially and financially it was an extremely strong deal," he adds. "Like our clients, we are always looking for ways to be more efficient and it's an extremely efficient building."

According to property research company CoStar, CMS currently pays rents of around £40 per square foot for Mitre House.

The first floor at Cannon Street will be a space for clients, with a 200 seat seminar space, meeting rooms and a 'technology hub'.

There will be no landline telephones in the office. Instead fee earners will have headsets and mobile phones connected to Microsoft's Lync platform, an online network to connect all of CMS' contacts.

The lease on Mitre House comes to an end in July 2015, with the exact date for a move dependent on negotiations with the relevant landlords.

CMS had originally planned to take up 200,000 square feet in Hammerson's Principal Place skyscraper when the Mitre House lease expired, but pulled out of discussions while the City tower was still under development in 2012 due to market uncertainty.

The firm's search for a new London office kicked off in 2008, with the firm now having moved away from its original vision of moving into a building with 300,000 square feet of space.

How effective is your law firm's IT? Complete this Legal Week survey for a chance to win an iPad Air: click here