Honda's record attempts on the Bonneville Salt Flats in Utah, USA, reached a fitting climax on Thursday when Alan van der Merwe piloted his Honda F1 car to three new land speed records, each eclipsing those set on the previous day, when the Bonneville 400 team finally reached a measured mile speed of 400kph.

Since Tuesday, van der Merwe and the team have broken FIA class world records three times over, ending up with an average speed of 397.360kph [246.908mph] over two runs of the Bonneville flying mile.

At the same time, van der Merwe set a new class record for the flying kilometre, with an average speed of 397.481kph [246.983mph]. Both speeds again set a new mark for the fastest officially measured speed by a Formula 1 car, pending official ratification by the FIA.

"I think in general the feeling is satisfaction with what we achieved," said van der Merwe. "It would have been nice to have a round number for the record and we are only 2 and half ks off that. In fact, we know we did everything possible to the car; we timed it exactly right today with the weather and we're pretty sure we couldn't have got more out of it, possibly another kilometre an hour but we would have needed freakishly good weather to do that.

"So, yeah, I'm really happy and slightly relieved as well, because it has been really stressful, every day, and we now know we have had the best day possible to run the car. And also the fact that the team did really well - the first thing to let go was the car; Altogether its been great to set the record and very rewarding to reach 400kph, its been a great week."

The atmosphere was full of anticipation on the final day of high-speed running, as the project team arrived on the salt flats in the hope the records could be raised. The team were ready to go as dawn broke, having carried out a gearbox change late into the previous night. van der Merwe rolled onto the course at 0640 local time and consistently recorded times above 390kph all morning until his record-breaking run at 0902.

Unfortunately the team lost a driveshaft late morning that damaged the differential and were forced to draw a line. However, having completed nearly three times a grand prix distance at Bonneville this week, in an extreme and hostile environment, as well as running at the Mojave, Lyneham and Victorville tests, the Honda 3-litre V10 was one of the stars of the show.

Mike Cook, president of the Southern California Timing Association (SCTA) and veteran of several land speed record attempts at Bonneville, was equally as pleased that the team had stayed on to push its own records even higher.

"First of all, I want to say we really feel the team came out and worked very, very hard right down the side; they are truly Bonneville racers now. We out here call them the Formula One Hot Rod now because they did everything humanly possible to make this car run as fast as it has," he noted.

"They accomplished a 246.980 average for the mile, which means they have increased their speed again, and they got a 397.481 so today was a success. They didn't get a 400 record but they got their 400 one-way run, so maybe it'll enthuse them to come back! Anyway, they got a record and they're going home with a record."

Bonneville 400 technical director, Gary Savage added: "Today we went racing, this is the racing truth isn't it? The only thing there is, is the stop watch, no excuses, no nothing, you just go for it. The team were fantastic they did everything on the car to get it to go quicker. We did hit 400 for one of our runs, we did 399kph for another and our average is 397kph so it's pretty good really."