Gérard Mestrallet, the man poised to become top boss of the world’s newest energy giant, GDF Suez, calls the marriage of the French titans “one of the largest mergers in France in the last 20 years”.

It’s also been among the most acrimonious. It’s taken two and a half years of back and forth bickering to seal a deal that many believed would never come to pass.

In a wonderful bit of understatement, GDF chief Jean-François Cirelli, the new company’s number-two executive, told his shareholders on Wednesday that bringing this merger to fruition required “intensive preparations”.

In fact, the road that led to this union was a legal, social and political minefield.

It’s worth a reminder where this Battle Royale actually started - with the French essentially telling the Italians to “get lost”. It was February 2006 and then Prime Minister Dominique de Villepin, under pressure in the polls, summoned Mestrallet and Cirelli to his workplace at the Hôtel Matignon to announce the creation of a new French national energy champion.

The idea in the back of everyone’s minds at the time was to fend off a possible hostile takeover bid from Enel, an Italian competitor.

Subsequent months saw a series of further snags.

A major sticking point from the beginning was that sealing this deal meant privatising Gaz de France, which the state owns 80% of. (The state will hold a 35% stake in the new company). You can imagine that many GDF workers smelled a rat, fearing that a proud heritage was being plundered. For many, the thinking was, ‘If it ain’t broke, why fix it?’ – and especially why ‘fix it’ via a merger with a private company bent on profits, possibly at the expense of public service?

Critics – not least among them France’s Socialist opposition – lambasted the whole affair as a dangerous move, despite all the reassurances to the contrary by the top brass.

They argued it would result in higher prices – something the heads of both GDF and Suez adamantly deny. Some union representatives, moreover, feared job cuts, which Cirelli also pointedly denied at Wednesday’s shareholder assembly.

Then there are European regulators. They have been eager to promote greater cross-border competition and transparency across Europe’s energy sector. Marrying two French giants is not necessarily Brussels’ idea of the best way to do that.

GDF and Suez retort that this is not about political or financial interests, but purely industrial ones. They say their objective is to forge a new entity up to the challenge of securing and providing energy in a Brave New Energy World.

The question though is whether such a mammoth is really needed – and whether it will be a juggernaut that crushes all competition in its path.

The combined company will be a beast, with a market capitalisation of 93 billion euros in market capitalisation, 22 million clients (half of them in France) and 200,000 employees. It’ll rank up there in the top trio of European energy groups, alongside E.ON of Germany and France’s EDF.

It will be the biggest natural gas buyer in Europe; and also enjoy a pole position in the burgeoning new market for liquefied natural gas – gas that can be super-cooled into liquid form and shipped by tanker.

But the fact is we’re seeing lots of consolidation in the energy market and size is seen as critical now in the face of soaring energy costs. Cirelli noted that energy consumption has been growing by about two-thirds with each generation. As energy resources become rarer and harder to get at in coming years, energy security will be a top priority, he said.

Here at home in France, the new company will have a feisty competitor in EDF – with whom it could soon be vying to build France’s next second-generation nuclear reactor.

And it will also have to reckon with – some would say, pay fealty to - the likes of Russia’s state gas monopoly, Gazprom.