Berwin Leighton Paisner (BLP) and Fladgate are among a line-up of law firms to have advised on some of the biggest football transfers this summer, amid a record-breaking transfer window for the Premier League.

According to Sporting Intelligence, the 20 clubs in English football's top division have already spent £1.185bn during this summer's transfer window, breaking last year's record of £1.165bn with a week still to go before the window closes.

Manchester-based sports specialist firm Centrefield, which was founded in late 2015 by a team of ex-Brabners lawyers, advised Manchester United on the biggest Premier League deal of the summer – the £75m signing of Belgian striker Romelu Lukaku (pictured) from Everton.

Everton took advice from its in-house legal team, led by head of legal services Chris Anderson. Anderson, a former corporate lawyer at Slaughter and May, has been at the northwest club since March 2014, when he joined as its first in-house lawyer.

Everton's legal team has had some assistance from a familiar face this summer, with former Irish international midfielder Gareth Farrelly, who spent two years at the club in the late 1990s, joining the team on a three-month secondment from City litigation firm Peters & Peters, where he is now a trainee following his retirement from football.

Farrelly's secondment has included work on player transfers, commercial partnerships and contracts, and he was also involved in the deal which saw Wayne Rooney return to the club on a free transfer after 13 years at Manchester United.

In another of the summer's biggest deals, London firm Fladgate took the lead role for Spain international Alvaro Morata on his £60m transfer from Real Madrid to Chelsea.

The deal is a club record for Chelsea, surpassing the £50m fee paid to Liverpool for fellow Spanish striker Fernando Torres in 2011.

Fladgate's sports business group head James Earl and sports partner Alan Wetterhahn led the firm's team on the deal. Earl commented: "Transfer deals of this nature are becoming ever more complex, reflecting the need for advice on a myriad of elements, including corporate, tax, regulatory, intellectual property, image and media rights, and employment."

Arsenal also set a new club record this summer with the signing of French striker Alexandre Lacazette from Lyon, in a deal valued at around £50m. The north London club has taken advice from Slaughter and May on many of its transfers in recent years, including the previous record signing of Germany midfielder Mesut Ozil in 2013, although the magic circle firm was unavailable for comment on whether it had any involvement in the club's transfer business this summer.

Elsewhere, BLP took the lead role in advising Nigerian striker Kelechi Iheanacho on his £25m move from Manchester City to Leicester City.

BLP fielded a team led by head of international commercial disputes Graham Shear, who acted alongside Simon Cliff, the general counsel of Manchester City's parent company City Football Group. Leicester City was advised by general counsel Caroline McGrory, who joined the club as its first-ever GC last December following their surprise 2015-16 Premier League success.

The biggest transfer of the summer, however, had no Premier League involvement – Paris Saint-Germain's world-record €222m (£200m) acquisition of Barcelona star Neymar.

Brazilian firm Bichara Abidao Neto advised Neymar, with Paris firm Nataf Fajgenbaum & Associes and Valencia-based firm Ruiz-Huerta & Crespo advising the Paris club on the deal, which eclipsed the previous record of €105m (£89m) paid to Italy's Juventus by Manchester United for French midfielder Paul Pogba last summer.