BAR Honda gained success in 2004, with Jenson Button becoming a regular podium finisher and Takuma Sato finishing third in the U.S. GP. However, as McLaren, Renault, and Williams, all lower in the rankings, were able to win races, BAR Honda finished second overall, just one step short of its long-sought championship victory.

In order to achieve its goal of winning the championship, Honda purchased BAR’s shares and established BAR Honda GP Limited. The team headed into the 2005 season as a full-factory team. The technical director was Jeff Willis, and a three-part technical organization was formed: BAR Honda GP, based in Brackley, England, HRD, the European base for engine development, and Honda R&D in Japan. The drivers were Jenson Button and Takuma Sato, as in the previous year. In the European rounds, Former CART Champ Car Champion Gilles de Ferrin joined the team as Sporting Director, adding much depth to the organization.

The BAR Honda 007 was BAR Honda’s first factory car. The 3-liter V10 engine was also restricted to maximum revs of 18,600 rpm due to the new two-race, one-engine rule. However, the engine was compact and lightweight, and its mid-range torque was improved for better drivability.

Off-season tests of the BAR Honda 007 were patchy. Sometimes the 007 had many problems and was unsatisfactory, and other times it was surprisingly fast and outperformed Ferrari and Williams. Onlookers had no idea of what to expect. There was both uncertainty and anticipation. It was under these circumstances that the 2005 season began.

In the opening round, BAR Honda faced a more difficult battle than expected. First of all, it was exposed as an aerodynamically sensitive car that was difficult to set up. This is largely due to the regulations that were changed in the name of “downforce reduction.”

At the beginning of testing, BAR Honda had reduced the amount of downforce from the previous year’s 006, and drove the “hybrid car” with downforce at the 2005 level. This became the development benchmark for 007. However, Takeo Kiuchi, Honda’s F1 project leader at the time, said this was too low compared to other manufacturers. “We set a benchmark that was 20 percent lower, which couldn’t be recovered, and ultimately affected us to the end,” he said. Furthermore, BAR Honda had set Ferrari as its performance target. Ferrari’s car that year, was truly a failure. Renault and McLaren were far ahead.

At the same time, lack of reliability, especially with the engine, and the Michelin tires, which had worked so well the previous year, did not match up well with the car. The team that had been on the podium every race last year found itself in a situation where they were getting nowhere. Button was eleventh and Sato 14th, a very poor start to the season for the team that was ranked second last year. In the second round, the Malaysian GP, Sato was unable to race due to a fever, and reserve driver Anthony Davidson was rushed in.

Nevertheless, the team seemed to have made remarkable progress since the start of the season. In Round 3, San Marino, Button and Sato returned to the top positions, finishing third and fifth respectively. However, tragedy awaited. A difference of interpretation with the FIA regarding the fuel tank structure came up, and the team was banned from the next two rounds in Spain and Monaco. Just when the team’s performance had finally picked up, they were sorely disappointed, sidelined.

In Canada, the second race back after the bans, Button took his first pole position in 22 races, and Sato qualified sixth, but both drivers retired from the race. In Round 9, the U.S. Grand Prix, the team was determined to make a comeback, but the race was effectively cancelled due to the Michelin users’ boycott, an incident that would go down in F1 history. The season progressed with BAR Honda unable to get out of neutral gear.

The team’s first points of the season came in Round 10, France, in which Button finished fourth. From this point on, Button’s performance remained consistent with two podiums and front row starts.

Sato was unable to gain any momentum throughout the season. He finished eighth in Round 13, Hungary, this was the only points finish for the season (points were awarded to the top 8). Despite his good qualifying performance, Sato was plagued by bad luck in the races, such as machine issues, refueling mishaps and cancelled qualifying times. Perhaps due to his impatience, Sato made his own problems, hitting Michael Schumacher in the Belgian Grand Prix, and then colliding with Jarno Trulli at the chicane in Suzuka, ending in a disqualification. Sato said after the season ended, “I struggled to get out of a bad situation, and I wasn’t sure how much effort I had to put in.”

In 2005, BAR Honda dropped to sixth in the constructors' standings, from second the previous year. However, there were some technological highlights, such as the seamless shift gearbox developed at the Honda R&D in Tochigi, Japan. The development capability of the team was also remarkable, as it returned to a top-class car by the end of the season despite various issues such as suspensions. However, delays in development at the start of the season and mistakes in setting development targets lingered until the end, and the team was unable to catch up with top contenders such as McLaren and Renault. The BAR Honda 007 was doomed to fight through an agonizing season.