For some time now, McLaren has been busy working on a successor to their legendary F1 supercar from the 1990's. And no, it wasn't the P1 nor was it the Senna. Instead, it will be the next Ultimate Series McLaren called Speedtail.

Previously called BP23, the F1's spiritual successor is claimed to be capable of speeds beyond 391km/h. At the time of its announcement, the British marque has not yet mentioned any info on how it reaching those speeds.

That is, until now.

McLaren boss Mike Flewitt recently spoke with Top Gear UK regarding some details of the Speedtail's powertrain and performance figures. According to Flewitt, the upcoming three-seat hypercar will continue to use the McLaren engine architecture we've become familiar with – the twin-turbo 4.0-liter V8 – but now it will produce over 1,000 horsepower. It will also be using hybrid system different from the P1 to help the Speedtail produce those power figures.

“That architecture has gone from 426bhp in a GT4 to I-can’t-tell-you-what-yet in a Speedtail. But it’s more than 1,000PS,” said Flewitt speaking to Top Gear UK.

The McLaren Speedtail will have more than 1,000 horsepower

Aside from the engine and power, no other details have been revealed regarding the Speedtail. All we know is that it will be the fastest McLaren to date. However, it won't be gunning for speed records such as the likes of Koenigsegg, Hennessey and Bugatti. Simply put, the Speedtail is built for more than just that. As mentioned previously, it will be a hyper-gt (grand tourer) - a vehicle you'd be comfortable going on an epic road trip with.

“It’ll be super comfortable, super to drive. It has an amazing top speed, but that’s a result of the engineering that’s gone into the car, not a target of the car. It was never a target. We’ve got simulations that tell us what it is, but we haven’t proven them yet,” added Flewitt.

The McLaren Speedtail is expected to be revealed later this year and is limited to 106 units. As expected, all 106 units have already been accounted for.