When Skadden Arps Slate Meagher & Flom won the lead role on the Qatar Investment Authority's (QIA's) £10.6bn bid for Sainsbury's through Delta Two, the mandate was understandably seen as a coup for the US firm's City arm. But with the deal's last-minute implosion there are recriminations and some questioning of the tactics of the bidders; where did it all go wrong for what looked like one of the most daring European deals of the year?

The deal collapsed just days before the deadline for a formal, fully-financed offer from the Qataris, with Delta Two unable to get its sovereign fund-backers to stump up an additional £500m in equity to bolster the company's pension funding. Given the swift downward turn in the markets after the debt-heavy bid was initially announced in July, it would be an obvious conclusion that the credit squeeze was the main culprit, but all parties agree that wider conditions were of minimal impact. Instead, some blame the QIA for being ill-prepared for what was always going to be a complex bid with substantial UK competition and pension issues. It is argued that a request to inject £500m to reduce the bid's reliance on debt was entirely predictable and reasonable.

As one partner close to the transaction comments: "Why would you choose one of the most difficult companies in the UK to take over as your first? With the family ownership, the Tchenguiz stake and the Office of Fair Trading requirements, Sainsbury's is very, very complicated."

Skadden corporate partner Adrian Knight led the US firm's team on the deal, which has left QIA as Sainsbury's biggest stakeholder after building up a 25% interest. The US law firm handed over real estate and pension work to Herbert Smith as it did not have the capacity internally; however, it did not pass on the competition aspects to Herbert Smith (which was conflicted) or any other UK firm – another factor that has drawn surprise.

Instead it relied on barristers at Monckton Chambers and its competition team in Brussels despite the significant UK competition issues associated with the bid which meant Delta Two had to prove that high debt levels would not leave Sainsbury's incapable of competing against rivals such as Tesco. Skadden declined to comment on the deal citing client confidentiality.

Whatever the reason for the collapse there is little doubt that all the advisers involved are not happy. While Linklaters, which took the lead for Sainsbury's, wins in the sense that it keeps its longstanding client, the air of disappointment at Silk Street is palpable.

"What could we have done differently?" asks Linklaters contact partner Mark Stamp. "The price was a good offer so the company would have been criticised if it had not taken it to shareholders. We did everything we could to reduce the risk as much as possible before due diligence could commence – but you cannot eliminate it entirely. To get to that stage and it not go ahead is not good for anybody."

Meanwhile, there will be four more disappointed law firms on the bid side with Shearman & Sterling, Cravath Swaine & Moore, Latham & Watkins and Sidley Austin all picking up roles for banks Dresdner and Credit Suisse. Aside from the advisers' disappointment, it will also be interesting to judge the deal's collapse on the credibility of sovereign-backed bidders in general. As one corporate partner who is not involved in the deal comments: "To get that far down the line and not be able to get the funding is bad. It was a bit of a learning curve for them coming in and they have not covered themselves in glory."