Barclays, RBS and the Nationwide Building Society's advertised legal vacancies surged during the first quarter 2015, new data from business intelligence provider Vacancysoft and recruitment consultancy JLegal shows.

UK banks are bulking up their in-house teams in response to an increase in financial regulation and a rise in new transactions as the economic recovery continues, according to Philip Jennings, head of private practice at JLegal.

He said: "The regulatory and contentious sides are big growth areas and banks need to bulk up in those areas. There are also efforts to reduce external legal spend so it's cost-effective for them as they can keep more of the work in-house."

In Q1 2015 Barclays topped the ranking of companies hiring the most in-house legal staff. The bank advertised 22 vacancies compared to five in Q1 2014, when it came 8th in the ranking.

It has already advertised just over 80% of the total vacancies it advertised in 2014, when it listed 27 vacancies.

During the first quarter of this year, Barclays saw three senior members of its in-house legal team announcing their resignations.

Judith Shepherd, Barclays Investment Bank global general counsel for corporate investment, announced that she would leave the bank in the first half of 2015, while managing director of litigation and investigations Jonathan Peddie revealed in January that he would leave at the end of February. Europe and the Middle East general counsel Erica Handling left at the end of March.

RBS and Nationwide have broken into this year's quarterly ranking in second and third place respectively. Neither had ranked in the top 10 companies advertising the most vacancies in Q1 2014.

Both banks have already advertised more vacancies during this quarter than the whole of 2014. RBS advertised 18 jobs compared to 15 in 2014, while Nationwide advertised 12 in Q1 compared to four last year.

In private practice the top three London firms hiring legal staff were Linklaters, Baker & McKenzie and PWC Legal, with the latter already advertising more vacancies in Q1 (15) than its total in 2014 (11). Linklaters also topped the Q1 2014 ranking with 13 vacancies, but Bakers and PWC Legal are new entrants to the list.

Firms build up in real estate

In private practice the new vacancies by practice area are dominated by real estate in London and across the country.

In Q1 real estate represented 16% of the 389 City vacancies advertised. Banking and finance accounted for 12% of London jobs advertised, followed by corporate and M&A at 9%.

Outside of London real estate accounted for 36% of the 842 vacancies advertised in Q1.

"Real estate along with corporate and transactions have been big growth areas for the past couple of years. Last year there was a big increase in real estate development work," says Jennings.

With in-house teams in particular showing a significant uptick in hiring staff, law firms may miss out on work, Jennings argues.

He adds: "The economy is doing well so general workloads are still very good in private practice. Are law firms losing out? Probably, as in-house legal teams increase [their staff] they do miss some work but the big deals will still go to external providers."