Fox Williams has instructed DAC Beachcroft to defend a £5.5m professional negligence claim over its representation of former EY Moscow CFO, Cathal Lyons.

Lyons’ claim the firm made crucial errors in its advice over his retirement agreement with EY will be heard in the High Court on 22 February.

The claim centres on allegations Fox Williams partner Tom Custance failed to include the option to choose English law and jurisdiction in the contract, which led to Lyons suffering a shortfall of more than £1m on his retirement payout.

The former financial officer left EY following a serious motorcycle accident in June 2006. He also alleges Custance failed to pursue insurance policies for disability, which would have covered Lyons’ medical costs.

Lyons has instructed SGH Martineau partner Kelly Tinkler on the claim.

A spokesperson for Fox Williams said: “We are confident of our defence to Mr Lyons’ claim.”

The firm’s defence denies allegations of negligence stating the apparent breach does not fall “within the scope of the defendant’s retainer”.

The claim was filed at the High Court in March 2014 by the claimants’ counsel Wilberforce Chambers’ John Wardell QC.

DAC Beachcroft partner Philip Murrin has instructed Devereux Chambers’ Colin Edelman QC and Ben Lynch for the defence.

Other firms to face professional negligence disputes in the last two years include: Clifford Chance, which settled the high-profile Excalibur dispute for an undisclosed sum earlier late last year; Withers, which was ordered to pay former client Wellesley Partners £1.6m in damages in November following an unsuccessful appeal; Gateley, which is set to fight a multimillion-pound claim by property developer client EPG in April 2017; Nabarro, which agreed to pay £10m to settle a £130m claim by a client in 2014; and Mishcon de Reya, which defeated a lawsuit by ex-QPR chairman Antonio Caliendo in February.

The legal line-up

For the claimant, Cathal Lyons

Wilberforce Chambers’ John Wardell QC, instructed by SGH Martineau partner Kelly Tinkler

For the defendant, Fox Williams

Devereux Chambers’ Colin Edelman QC and Ben Lynch, instructed by DAC Beachcroft partner Philip Murrin