Freshfields Bruckhaus Deringer is moving to draw a line under its controversial role on the bid for Marks & Spencer (M&S) after the Court of Appeal last week refused to lift an injunction barring the firm from acting on the £9bn bid.

The judges, Lord Justice Kay and Lord Justice Pill, ruled on 3 June that the effective use of Chinese walls in a non-agreed takeover was "wholly improbable".

The court heard how Fresh-fields set up an information barrier one month after accepting an instruction to act for Philip Green when it became clear that the employment contract of Per Una head George Davies, on which Freshfields had advised, was to be a key issue in Green's bid.

In the judgment, Kay said: "I find it surprising that it took the due diligence application to put them [Freshfields] on the alert." Pill added: "I have little difficulty in concluding there was a clear conflict of interest."

The judges also took into account other work Freshfields had done for M&S, citing knowledge of the iconic retailer's pricing policy and supply chains.

Freshfields offered to relocate lawyers working on the bid as well as signing confidentiality documents saying they would not receive confidential information from previous work for M&S on the deal. Responding to the offer, Pill said: "In my view, it is far too late in the day for promising further measures."

Freshfields had accepted the instruction in early May and took the view that its work for M&S and on the George Davies contract, which it has worked on "from time to time" since 2001, would not be seen by the corporate team working on the Green bid.

Chief executive Hugh Crisp led the conflicts check and subsequently informed Green the firm would be able to do the deal, with head of corporate finance Barry O'Brien leading the team.

The firm did not inform Green about its work on the Davies contract, but when it became aware that it would be an issue, it employed a "more formalised Chinese wall". This involved security labelling on files, separate filing cabinets and not allowing changes to team personnel.

Ashurst is now advising the Philip Green consortium, which promises to be a massive boost for the firm's corporate profile. Head of corporate Chris Ashworth is leading the team on the deal.

Ashurst secured the instruction on 3 June ahead of potential candidates, including Lovells and Linklaters, which was understood to be ready to take on the instruction from its arch M&A rival.

Slaughter and May corporate partners Nigel Boardman and Andy Ryde are leading the team for M&S, with litigation partner Sarah Lee called in on the injunction.

Michael Brindle QC of Fountain Court was instructed by Freshfields, while Slaughters turned to Kenneth MacLean QC of One Essex Court.

The episode will now be watched closely for its impact on Freshfields, with City rivals questioning the firm's stance in accepting the Green instruction.

One head of corporate at a top 10 London firm told Legal Week: "It is difficult to see how Fresh-fields will come out of this. One thing is for sure, I am very glad we are not in their shoes."

Another partner added: "Even though I am not a retail specialist, I knew that George Davies is central to the M&S bid. It is one of the issues that must have been high on their radar screen."

Talking to Legal Week, Fresh-fields' Crisp strongly defended the firm. "The judgment emphasised a perception of risk, but that risk did not come to pass," he said. "I do not believe Slaughters and M&S thought we would disclose confidential information. It is good for them to get the team of first choice off the deal." He added the firm would not be changing its conflict-checking procedure.