The Solicitors Disciplinary Tribunal (SDT) has ruled that the Leigh Day lawyers acquitted of professional misconduct will not recover their legal costs.

The human rights firm applied to have 75 per cent of its total costs – thought to be £7.5m before the SDT hearing – covered by the prosecuting body, the Solicitors Regulation Authority (SRA), after the tribunal dismissed all of the allegations of misconduct against the firm’s co-founder Martyn Day and solicitors Sapna Milk and Anna Jennifer Crowther.

The three solicitors were accused of pursuing false claims of torture and murder made by Iraqi civilians against British troops in Iraq. They were later cleared by the tribunal after the allegations were found “not proved”.

The SDT said in a statement: “Following the hearing on the 13 November, the tribunal orders that there be no order for costs in relation to the substantive hearing.”

Leigh Day will have to lodge an appeal by the 21st December if it wishes to contest the decision.

A spokesperson for Leigh Day said: “We are disappointed, given the fact that over 250 charges against the firm and colleagues here were found unproved, we believed it was appropriate to seek some measure of the costs involved – paid both by ourselves and by our insurers – in defending ourselves.  However, we respect the decision of the SDT in what was an unusual application.”

Leigh Day was first instructed in 2007 by a number of Iraqi citizens who sought compensation from the Ministry of Defence.

They alleged they were unlawfully detained, injured or killed by British forces in Iraq in a 2004 incident known as the “battle of Danny Boy”.

The Al-Sweady inquiry was launched in 2009 to analyse the claims, concluding five years later that the “allegations of torture and murder are untrue and that all of the 28 dead were killed in fighting with British forces”.

Leigh Day and Public Interest Lawyers were the subject of criticism by defence secretary Michael Fallon in 2014 following the publication of a report into allegations that British forces tortured and executed Iraqi citizens.

The charges against the Leigh Day lawyers were brought by the SRA at the end of 2015 and published last summer.

Russell-Cooke partner Paolo Sidoli represented the regulator, who accused the firm of failing  to provide copies of documents to the Al-Sweady inquiry and “maintaining allegations of unlawful killing”.

The SRA said last month that it was planning to appeal the SDT’s decision to acquit Day and his colleagues.