As McLaren prepare for their final Grand Prix with maligned engine suppliers Honda, Sky Sports F1 looks at the defining moments of the failed partnership.

2014 debut test woe - a sign of things to come

Looking back, McLaren's reunion with Honda appeared cursed from the very beginning.

The renewed partnership immediately suffered severe teething problems with the Honda engine's debut limited to just five laps across two days of post-season testing in Abu Dhabi in November 2014.

While McLaren sought to take positives from the event - "It's definitely been a positive for both McLaren and Honda to conduct this test - there have been some troublesome issues, but we've made progress," racing director Eric Boullier said at the time - Abu Dhabi would prove to be an ominous sign of things to come.

The McLaren-Honda is recovered to the pits at the 2014 Abu Dhabi test

Pre-season testing 2015 - more signs of trouble

Despite that early setback, many believed that with Honda entering the hybrid era of Formula 1 a year later than the rest of the field, and a winter to try and resolve the problems from Abu Dhabi, they would avoid the struggles of pre-season testing that had plagued Ferrari and Renault in 2014.

How wrong that proved to be!

Fernando Alonso, back with the team for the first time since his acrimonious departure in 2007, was limited to just six laps on the opening day of testing in Jerez with Jenson Button only managing the same number on day two.

Throughout the 12 days of testing in February and March 2015, McLaren only managed more than 40 laps in a session twice and found themselves over two-and-a-half seconds slower than the pace set by the all-conquering Mercedes W06.

McLaren confirm Honda divorce

2015 Australian GP - starting from the back...and not at all

McLaren's troubles became stark in the season-opener at Melbourne as the eight-time Constructors' champions found themselves in the ignominious position of propping up the rest of the field.

With the newly-revived Manor team failing to take to the track, Button and Kevin Magnussen - standing in for the concussed Alonso - qualified 17th and 18th respectively to fill the back row. The Australian heat had forced Honda to run their engine conservatively, resulting in laps three seconds off Mercedes' pace in Q1 and over five seconds off Lewis Hamilton's pole time.

Come race day and Magnussen would not even see the lights go out as his engine gave up as he made his way to the grid.

Button, meanwhile, would be last of the 11 cars to finish and the only driver to be lapped twice.

2015 Hungarian GP - Alonso records joint-best finish

After Button collected the first points of the McLaren-Honda partnership since the 1992 Australian GP in Monaco, Alonso claimed his first point since returning to the team at Silverstone before following it up with a fifth-place finish at the Hungarian GP.

The Spaniard out-performed his car by climbing from 15th on the grid and overcoming a puncture that had required an emergency pit-stop. With Button finishing ninth, Hungary also represented the first double-points finish for the revived partnership.

But two years later, Alonso's fifth place still remains McLaren's joint-best finish since reuniting with Honda, along with the two-time world champion's results in the 2016 Monaco and US GPs.

Record grid penalty at Spa

The problems with the Honda engine came to a head when McLaren were handed a record 105-place grid penalty at the 2015 Belgian GP.

With Alonso and Button having already used up their allocation of five engines, the duo were handed penalties of 55 places and 50 respectively to leave them at the back of the grid after Honda introduced an upgraded engine following the summer break.

Then-Honda F1 boss Yasuhisa Arai had claimed the upgrade would see the McLaren match the pace of Ferrari but it would prove to be a false promise. At the power-dependent circuit, the lack of performance in the Honda engine was once again laid bare as Button and Alonso could only manage 17th and 18th in qualifying.

Why McLaren had to divorce Honda

2015 Japanese GP - 'GP2 engine'

In Suzuka, Alonso's frustration with McLaren's dismal 2015 finally boiled over. At Honda's home race, Alonso described the team's performance as "embarrassing" and yelled over team radio "GP2 engine, GP2" after being passed down the back straight.

McLaren's Fernando Alonso described the team's performance as "embarrassing" at the 2015 Japanese GP McLaren's Fernando Alonso described the team's performance as "embarrassing" at the 2015 Japanese GP

2016 improvement fuels lofty ambitions

After the troubled first season of the revived partnership, things could not get any worse and 2016 did see McLaren-Honda make some big steps forward. They reached Q3 for the first time at the Spanish GP and would go on to be regular participants in final qualifying - although the sight of this modest progress being celebrated was a sign of just how far the former champions had fallen.

In total, the team achieved 17 points finishes - compared to six in 2015 - although they remained off the podium and led to former McLaren boss Ron Dennis rating the season as only "five out of 10".

But the relative improvement had McLaren and Honda chiefs predicting the team would be fighting Mercedes in 2017. "We have a plan to challenge Mercedes in 2017," Honda's head of F1 Yusuke Hasegawa said, while Boullier predicted: "I think we will get closer. I don't know if we will match them, I hope so, but we will get very close."

Nightmare winter of 2017

But for all the positive talk, F1 2017 would prove to be a return to the dark days of 2015. Winter testing in Barcelona was a disaster. The new MCL32 spent nearly as much time on the recovery lorry as it did on track and culminated in four breakdowns over the final two days.

McLaren completed the fewest laps over the eight days of testing while their fastest lap was nearly three seconds off the pace set by Ferrari. The performance led Alonso to deliver a withering rebuke of McLaren's engine suppliers, stating the Honda power unit had "no reliability" and "no power".

Sky Sports F1 revealed that unexpected vibrations in the Honda engine were effectively shaking itself into breaking down.

Speaking on the F1 Report - Testing Special, our guests think McLaren are a team in crisis following a disappointing display at testing in Barcelona Speaking on the F1 Report - Testing Special, our guests think McLaren are a team in crisis following a disappointing display at testing in Barcelona

It was also in Barcelona when reports first emerged that McLaren were considering a split from their maligned engine suppliers. Boullier admitted to Spanish publication AS that the team would be winning if they were powered by Mercedes while McLaren confirmed to Sky F1 that they were "considering options" following claims they were looking to return to their former suppliers.

'McLaren-Renault can be winners'

2017 Bahrain GP - Engine change after engine change

Perhaps the worst race weekend of the lot for McLaren-Honda. Five engine failures, an irate Alonso on team radio and dropping to the foot of the Constructors' Championship behind Sauber.

Three of those engine failures befell the unfortunate Stoffel Vandoorne, who did not even make the start as his power unit gave up on his out-lap from the pits.

Alonso had suffered his own MGU-H failure in qualifying before raging at Honda's lack of performance in the race. "I've never raced with less power in my life," he fumed, with his top speed of 285kph being 14kph slower than Hamilton's best. The Spaniard would retire late on due to "some problem with the engine".

It was another difficult day for McLaren in Bahrain and Fernando Alonso voiced his displeasure over their performance over team radio before retiring It was another difficult day for McLaren in Bahrain and Fernando Alonso voiced his displeasure over their performance over team radio before retiring

And it was in Sakhir where McLaren publicly turned the heat up on Honda. "We need to get on top of this problem, our partner needs to get on top of this problem and we need to do it quickly. But unfortunately there are no quick fixes in this sport," Zak Brown told Sky Sports F1.

Mclaren's executive director Zak Brown spoke candidly after the Bahrain GP Mclaren's executive director Zak Brown spoke candidly after the Bahrain GP

2017 Canadian GP - Divorce on the cards

The build-up to, and the race weekend itself, of this year's Canadian GP appeared to be the clearest indication yet that McLaren had decided to part ways with Honda.

It was in Montreal where the dialogue moved away from simply putting pressure on Honda to get their act together to indications that divorce papers were being drawn up. In an extraordinary interview with Reuters, executive director Zak Brown delivered a series of stinging criticisms of Honda, stating "they seem a bit lost", "we can't sit around forever", "they are struggling to get it to come together", "we have serious concerns" and "we're near our limit".

And, perhaps most significantly, Brown stated that, unlike his predecessor Dennis, he believed McLaren could win another world title with a customer engine.

McLaren's philosophy stops working

Alonso followed this by stating it was "maybe time to change the situation" in his pre-race press conference.

On track, it was the same story that had been played out so often in the two-and-a-half-year partnership as a fresh Honda engine failure denied McLaren their first point of the season. "Completely unacceptable" was Boullier's verdict.

And after a further five race retirements and 220 places worth of grid penalties for engine component changes, McLaren finally pulled the trigger at the Singapore GP to switch to Renault power from 2018.

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