Partners from White & Case and Orrick Herrington & Sutcliffe have topped a new ranking of the UK's most active deal lawyers by volume in the first half of 2017.

Data from Mergermarket shows White & Case private equity co-head Ian Bagshaw (pictured) topping the table, which covers a slow H1 by deal volume, alongside Orrick City corporate partner Anthony Riley. Both had roles on eight deals during the period, with Baghaw's deals worth a total of £5.7bn and Riley's worth £21m.

Top deals for Bagshaw include acting for Bridgepoint on its £750m acquisition of Zenith, the UK's largest independent vehicle leasing business, from private equity company HgCapital.

He also advised energy investment vehicle Harbour Energy on the $3bn (£2.3bn) acquisition by Chrysaor of a portfolio of North Sea oil and natural gas assets from Shell UK and its affiliates.

Other high performers by volume of deals include, in third place, Addleshaw Goddard Manchester private equity partner Paul Medlicott, who acted on seven deals worth £262m; and in fourth, DLA Piper Manchester private equity partner James Kerrigan, who advised on six deals worth £62m.

Of the 15 lawyers, Bagshaw advised on the highest total value of deals in H1, followed by DLA Piper's European private equity head Tim Wright (£2.86bn) and White & Case London private equity partner Caroline Sherrell (£2.59bn), who was the only female partner to make the cut.

Key deals for Wright include acting for UK health food retailer Holland & Barrett's management team on its £1.8bn sale to L1 Retail, which is part of Russian billionaire Mikhail Fridman's LetterOne investment business. Meanwhile, Sherrell acted for Infracapital and InfraVia on the acquisition of Italian container terminal operator Gruppo Investimenti Portuali.

Only one magic circle partner makes an appearance, with Slaughter and May City corporate partner Murray Cox in 15th place, having advised on four deals worth £662m.

Mergermarket does not rank individual partners by deal value.

The rankings come against a backdrop of a slowing UK deal market. While UK deal values nearly doubled in H1 2017 compared to the equivalent period in 2016, rising from $48.6bn (£37.6bn) to $93.7bn (£72.6bn) this year, deal volume fell by about 10% to 660 transactions – the lowest H1 total for the UK market since 2013.

Global deal value rose by 8% to $1,492bn (£1,156bn), while worldwide deal volumes slumped by 12% to 8,052 – also the lowest total for four years.