Allen & Overy (A&O) and Indian best friend firm Trilegal have scooped the mandated lead arranger mandate on the closing Bharti Airtel – Zain $9bn merger, alongside AZB & Partners, Herbert Smith and Linklaters.

A&O London banking partner Sanjeev Dhuna and associate Denise Gibson led the team for mandated lead arranger and lead adviser Standard Chartered Bank.

The international firm drew in its Indian best friend Trilegal, where Mumbai partner and banking & finance head Karan Singh provided local Indian law financing advice to the banks.

"Trilegal are our good friends," said Dhuna, explaining that the deal had come to A&O through the lead bank. "I work quite a bit with Standard Chartered and I am their global relationhip partner," he said, adding: "I did quite a lot of India work anyway. They know me in India and know me globally and I have quite a good relationship with Bharti."

Standard Chartered, Barclays, State Bank of India and the rest of the financing consortium are providing $8.3bn (Rs 37,000 crore) in loans, according to news agency Reuters.

AZB's Delhi office advised Bharti Airtel together with Herbert Smith, while Linklaters was leading the team for Kuwaiti telecoms company Zain, as first reported on Legally India in February.

Dhuna also told Legally India that India was a very active banking market. "The borrowings by Indian corporates has gone up year on year, despite the fact that there is a credit crunch."

He added in the press release: "This deal illustrates Indian corporates' appetite for significant and strategic outbound investments. As India's primacy on the international stage continues to grow we expect to see more of these high-profile acquisitions. The financing also highlights the extent of liquidity in the Indian debt markets."

Due diligence for the Bharti Airtel - Zain merger has now completed and signing is expected "in the next few days", according to Reuters.  

It is the second-largest cross-border takeover by an Indian company, after Tata Steel's $13bn buy of Corus in 2007.

Dhuna also confirmed that he had acted for the banks in last year's ill-fated $23bn merger talks between Bharti Airtel and South African telecoms major MTN, which were scrapped late last year after protracted negotiations.

AZB, Freshfields Bruckhaus Deringer and Platinum Partners had advised on the second unsuccessful Bharti-MTN deal.

Dhuna said that he was also involved on the first unsuccessful talks between Bharti and MTN in May 2008.