Where to now for Red Bull?

Oh what a tangled web is being weaved between Red Bull, Renault and Mercedes, but then such political machinations and complications are part of the very fabric that makes Formula 1 what is today.

The fallout between Red Bull and power-unit supplier Renault has been long and painful this season, and with what appears to be a complete breakdown of trust between the two parties, a divorce is now imminent.

Despite a contract being in place through to the end of 2016, the understanding is that Red Bull has officially notified Renault in writing of its intention to terminate the deal at the end of this year.

As you can imagine, that has not gone down too well within the walls of Renault's headquarters at Viry.

Red Bull, however, is prepared to activate clauses in the contract relating to performance, or as they would likely point out, the lack of it on Renault's part this season.

Currently in their ninth year together after starting out in 2007, the four seasons of glory from 2010-13 have almost - but not quite - been forgotten.

Together the pairing won four consecutive drivers' and constructors' titles, with Sebastian Vettel behind the wheel, took the chequered flag in 41 grands prix and claimed 52 pole positions during that time.

A Sebastian Vettel and Mark Webber 1-2 in China in 2009 started a run of Red Bull-Renault success... © LAT

Those days have been replaced by 18 months of acrimony, bitterness and mud slinging as the 1.6-litre V6 turbo-charged power-unit era has, for the most part, proven a nightmare.

Heading into the Italian Grand Prix at Monza, where power is an absolute necessity, Horner has already issued a warning that drivers Daniel Ricciardo and Daniil Kvyat will both likely have to move onto their sixth engines of the season, so incurring a 10-place grid penalty.

It is a strategic hit to ensure Red Bull can be more competitive in the race that follows, around Singapore's Marina Bay Street circuit, which will be more to the RB11's liking.

But that is not the way Horner wants to go motor racing, having to take a penalty simply to ensure they have a chance of running Mercedes close in one particular race.

So given the rumours that swirled around the paddock at Spa-Francorchamps, it is unsurprising the sight of Daniel Ricciardo's retirement with what appeared to be an energy recovery-related failure - and therefore the fault of Renault - raised his ire yet again post-race.

Horner feels the problems within Renault run deep as he said: "You need to do a root-and-branch review. There are some very capable people around, but it feels under-resourced."

To rub salt into Renault's gaping wounds, Horner then highlighted Renault's deficiencies further compared to rivals Mercedes and Ferrari.

... that has been replaced by a disastrous 18 months in the new power-unit era © LAT

"You can see the effort and commitment that is going in from Mercedes," he added, "and the commitment from Ferrari as well - an enormous amount of resources being committed."

There is no way back from remarks like that, and a clear sign Horner is courting the only options available to him if Red Bull is to remain in F1 beyond 2016.

Part of Horner's frustration is the fact Renault is on the brink of announcing it is to again return to being a works team, with talks regarding the purchase of Lotus at an advanced stage.

Negotiations have been ongoing for months, during which time Renault has also sounded out the possibility of acquiring a majority stake in Force India.

In contrast to Lotus, discussions with Force India are only at a preliminary level, with Renault covering all bases should a potential return to Enstone fall through at the last minute.

Numerous hurdles have had to be cleared with regard to a purchase of Lotus, with a few still remaining before the French manufacturer can proclaim to be a works entrant again.

For Red Bull, that would mean the end of its number one status with Renault, certainly as far as the remaining year of its contract with them is concerned.

It is one of the main clauses in the deal, and so arguably could be singled out as a potential breach and another reason to try to break away early.

Renault's Cyril Abiteboul and Red Bull's Helmut Marko and Horner have had lots to discuss in 2015 © LAT

Publicly for now, Horner is calling on Renault to declare its intent for the future so Red Bull can then forge ahead with its own plans.

Do not think for one second, however, Horner is simply waiting for a phone call from Renault Sport managing director Cyril Abiteboul to inform him of the French manufacturer's intentions.

While Horner insists owner Dietrich Mateschitz's comments regarding Red Bull's potential withdrawal from the sport should not be taken lightly, it is inconceivable they would leave.

Hence why Red Bull is eyeing up a Mercedes engine deal, with approaches already made, as the former would be foolish to sit on its hands and wait.

Mercedes motorsport boss Toto Wolff previously refused to entertain the idea, but over time his stance has softened to such an extent he can now see the two sides of the argument as to why a supply deal would be beneficial, but then also potentially damaging.

"If you look at it from Mercedes' perspective it is probably the wrong thing to do to supply an engine to a fifth customer as it would put stress on the organisation," Wolff told AUTOSPORT.

"Additionally, supplying one of your championship contenders with big resources, it needs to be carefully judged and balanced as to whether we would want to do that.

"But then from a global perspective, Red Bull is a really phenomenal brand that attracts younger audiences and consumers.

Red Bull knows Mercedes power presents its best chance of fighting for titles again © LAT

"Therefore you cannot wipe it off the table and say, 'From the team's perspective it doesn't make any sense, so we are not looking at it'.

"No, you carefully analyse the pros and cons, and then obviously make a decision."

As the dominant team in F1 at present that position would undoubtedly come under threat should Red Bull, which knows how to make winning racing cars given its aerodynamic strength, suddenly possess the best engine.

On the flipside, aiding another customer team could put greater distance between Mercedes and its biggest rival at present in Ferrari.

For now, Wolff is rightly playing the political game by saying that until the issues between Red Bull and Renault are resolved then it is not Mercedes' position to interfere.

That is primarily due to the fact Mercedes and Renault are involved in a number of initiatives on the road car side.

It is highly likely Dieter Zetsche, chairman of the board of directors of Mercedes' parent company Daimler, would have no desire to annoy his Renault counterpart Carlos Ghosn.

It is why a Red Bull tie-up with Mercedes engines is far from cut and dried come the day Renault finally shows its hand, as there remain many political moves to be made behind the scenes.

But come the conclusion to the manoeuvring behind the scenes expect at some stage over the next few weeks for Renault to confirm its buy-out of Lotus, paving the way for Mercedes and Red Bull to become unlikely bedfellows.