London firm Salfiti & Co has been issued with a summons for failure to pay an expert witness.
This is the third action taken against the firm this year relating to the payment of expert witnesses or translators.
In July the firm was ordered to pay a translator who acted on its behalf in a hijacking case.
It is now defending two other actions. The first alleges failure to pay a psychologist, Georgia Costa, for expert opinions to the tune of about £11,000.
Salfiti has issued a counter-claim, alleging duplication of invoices and questioning Costa's qualifications.
The most recent summons was lodged earlier this month by the National Union of Journalists' (NUJ) legal department, on behalf of Dr Alan George, a leading Middle East specialist. George claims he was engaged by Salfiti & Co as an expert witness in the same hijacking case as Costa and is owed about £10,000 by the firm.
Salfiti is disputing the terms of the agreement between the firm and George, and has filed a defence to the claim.