Russell Jones & Walker is being sued by the UK's largest union the GMB over the treatment of a number of the firm's employees.
The general workers' union is filing a complaint to the Employment Tribunal on behalf of a handful of Russell Jones fee-earners following a review of the firm's bonus scheme last year. The claim is for an unlawful deduction of wages.
The GMB was involved in the initial consultation process over the changes, but it is now alleged that a number of lawyers are losing up to 17,000.
There was previously an annual executive bonus of 20 per cent over and above financial targets, but that was reduced and the award based on overall contribution to the firm increased.
Fee-earners now receive 10 per cent over financial targets and, according to a GMB spokesperson, most lawyers are failing to make up the original amount when using the merit-based scheme.
Four lawyers are bringing the case in London and there are a number of others in the regional offices.
"We recognise that, as with any such initiative, not everybody wins at first - Russell Jones spokesperson
A GMB spokesperson said: "At this stage, we're making sure we protect our members and don't file the claims too late. It could still settle and we're trying to continue consulting and negotiating. We'd like to reach a compromise, but we want to make sure that our members don't lose out."
A source close to Russell Jones said that most of the firm's staff are benefiting from the changes. "There are only one or two that are losing out," he said. "But whenever changes are made, there are always one or two people that claim they've lost out."
A Russell Jones spokesperson said: "The clear intent of the new scheme has been to provide a more balanced merit-based scheme alongside the conventional financially-based one. We recognise that, as with any such initiative, not everybody wins at first.
"We recognise that the few people adversely affected in this instance have a right to air their views and will continue to be dealt with seriously and sympathetically."