By Freya Berry and Sinead Cruise

LONDON (Reuters) - Fees from Royal Dutch Shell's $70 billion takeover of British energy firm BG could be among the top 10 most lucrative transactions on record, according to estimates from Thomson Reuters and Freeman Consulting. 

Shell's cash and share offer, recommended by the board of BG on Wednesday, could earn its three financial advisers a combined $182.6 million in fees, according to the estimates.

That would make the deal the eighth-biggest global payout for an M&A transaction. It is the biggest acquisition to be announced this year.

It is expected that Bank of America Merrill Lynch will earn approximately $82 million advising Shell, while Goldman Sachs and advisory boutique Robey Warshaw LLP will earn approximately $50.3 million each for their work for BG.

The largest ever fees from an M&A deal were the $530.7 million collected by banks on the acquisition of Mannesmann AG by Vodafone in 1999.

The limited number of advisers on the Shell/BG deal contrasts with many major deals which have historically involved at least two and sometimes three or four financial advisers to each party.

Nine banks shared the spoils when Glencore took over Xstrata in 2012, while seven are handling the merger of Holcim and Lafarge and related asset sales.

None of the parties involved has provided details on their likely earnings from the BG deal.

To keep talks between Shell and BG confidential, the list of advisers was intentionally kept short, one source familiar with the deal said, even though this meant Bank of America Merrill Lynch underwriting Shell's borrowing alone. Shell is contacting around 20 "relationship banks" to help put together a further bridge loan, two sources familiar with the matter said.

Merrill Lynch was already the top bank by fees and market share for the energy and power sector in the first quarter of 2015, with a 7.9 percent share, according to Thomson Reuters data. The bank came fourth for global mergers and acquisitions in terms of fees.

Goldman was at number one, after boosting its fee intake by 40 percent against the same period last year.

Investment banking fees for the energy and power sector reached almost $2.4 billion, the third most lucrative sector globally for the quarter.

Robey Warshaw's role deals another blow to major bulge-bracket banks, coming just weeks after independent investment banks Lazard and Centerview Partners LLC saw off bigger rivals to advise H. J. Heinz and Kraft Foods on a $46 billion merger.

The company began operations just last year under its two star dealmaker founders -- Simon Robey and his namesake Simon Warshaw.

Dealmakers across the City are now expected to try to flush out possible counter bidders to defend their positions in the league tables, which help companies select which banks and advisers they want to spearhead takeovers and share offerings.

"BG has long been mooted as a potential target for a number of predators. It is not inconceivable that this deal flushes out a counter offer for BG," one of BG's 15 largest investors told Reuters.

(Additional reporting by Pamela Barbaglia and Sophie Sassard; Editing by Keith Weir)