Deloitte arrived late to legal services. It only got its ABS licence to practice law in the UK in June last year, while all three of its major rivals had been doing so since 2014.

But just four weeks into the job as Deloitte's new head of legal, Michael Castle, ex-senior partner and formerly a managing partner contender at Allen & Overy, has decided he is not prepared to play catch up, but has a plan for some smart technological leap-frogging.

His external growth strategy includes partnering with other law firms for specific projects, forging alliances and buying firms that would complement the firm's overall offer. Internally, he wants to grow staff numbers and generate more work from cross-business referrals.

He said: "What sets us apart is Deloitte's reputation for consultancy and tech capabilities. We have this strong reputation, and are now able to unleash this on the market.

"Entering the market now is the right time because you can see how tech patents over the past few years are growing so rapidly."

Castle said Deloitte's legal arm creates a cohesion of the three sections of the legal market: private practice law firms, alternative legal providers, and legal technology companies.

Michael Castle, Deloitte head of legal

"What sets us apart is Deloitte's reputation for consultancy and tech capabilities… [which we] are now able to unleash on the market"

"Our brand is legal solutions, as opposed to just legal advice, with advanced knowledge of consulting and legal technology combined," said Castle.

He also aims to encourage companies to outsource, to contain cost and resource pressures on in-house teams and grow Deloitte's legal management consulting, which offers consulting to legal teams, either in-house or in private practice.

Castle began his new role at the start of February. Deloitte currently has 2,500 legal professionals worldwide, compared with PwC which has 3,500, KPMG which has 2,300, and EY which has 2,200.

When using a partnering technique to work with law firms on particular pieces of work, Castle said: "We'll target areas where law firms are providing top-quality advice, but where we can partner with them to create a smart, technology-driven model that really works in the current market."

This has been done once so far, when Deloitte partnered with Castle's former firm A&O.

Deloitte struck an agreement last year with U.S. immigration law firm Berry Appleman & Leiden, and has said it will look into further alliances.

Castle said acquisitions will also be considered but there will also be a focus on internal growth through referrals. Deloitte will use contacts with clients across the board to refer work to other parts of the business.

Castle said: "Work referrals work both ways. So if a consulting team in Deloitte is working with a client, they can also offer our legal solutions advice.

"And then part of my job is encouraging synergies between different teams in Deloitte, so if I'm working with a client on legal advice, we can give them cohesive legal, consulting and tech advice at the same time."