Deloitte and one of its former partners have been accused of misconduct over their links to the businessmen who presided over the collapse of British carmaker MG Rover.

The Accountancy and Actuarial Discipline Board, a regulator, has decided to haul Deloitte’s UK arm before a public tribunal to answer for an array of alleged failures related to the scandal.

Maghsoud Einollahi, a retired Deloitte corporate financier who played a prominent role in the affair, has also been targeted by the disciplinary action, which comes amid a broader regulatory crackdown on the biggest accountants.

The AADB’s accusations concern Deloitte’s relationship with the Phoenix Four, the now notorious quartet of businessmen who led the purchase of MG Rover from BMW, the German carmaker, in 2000.

The four men – John Towers, John Edwards, Nick Stephenson and Peter Beale – were disqualified as directors last year after controversy over the large financial rewards they extracted from the company before its failure in 2005.

Deloitte gave corporate finance advice to the Phoenix Four and MG Rover in addition to being the auditor to the group.

The apparent conflicts of interest in such arrangements are a growing concern for the European Commission, which wants the “Big Four” auditors – PwC, Deloitte, Ernst & Young and KPMG – to hive off their consulting arms in the European Union to ease independence fears.

The AADB’s complaint alleges that Deloitte and Mr Einollahi, who retired from the firm in 2008, failed to “adequately consider the public interest” in certain transactions as well as “the potential for there to be different commercial interests between the Phoenix Four, MG Rover Group and associated companies and shareholders”.

It also claimed they had not paid enough attention to “the conflicts of interest and self-interest threat” arising from working for both the Phoenix Four and MG Rover.

The complaint is understood to relate to two transactions. One involved the acquisition of most of BMW Rover’s loan book. The other involved the exploitation of tax losses.

However, Deloitte’s auditing of MG Rover has not been challenged by the AADB, an arm of the Financial Reporting Council.

The complaints will be heard by an independent tribunal nominated by the AADB, which has the power to issue an unlimited fine.

Deloitte said: “We are disappointed that the AADB has taken the view that limited aspects of our advisory work relating to two transactions in 2001-02 falls short of acceptable standards.”

It added: “We do not agree with the AADB and are confident that when all the evidence is considered, the tribunal will conclude that there is no justification for criticism of either Deloitte or our former partner Mr Einollahi.”

Mr Einollahi could not be reached for comment.