Mercedes have revealed Lewis Hamilton would have been forced to retire from the British Grand Prix were it not for a timely red flag.

Formula One title rivals Hamilton and Max Verstappen collided during a sensational first lap at Silverstone.

Hamilton was handed a 10-second time penalty that he disagreed with but Red Bull argued was not severe enough.

The Briton recovered to record a famous race win, while Verstappen ended up in hospital for checks after a 51G impact with the tyre barrier.

It meant Hamilton cut Verstappen's lead to just eight points in the drivers' championship.

But the outcome would have been very different had the race not been red-flagged to repair the barrier, as Hamilton would not have been able to continue without the opportunity to repair damage to his wheel rim.

"We'd failed the rim where we'd had the contact on the front-left, so that would have been a DNF had it not been red-flagged," said Mercedes trackside engineering director Andrew Shovlin.

"The rest of the damage was actually remarkably little. A tyre temperature sensor had got knocked loose, so it was waggling around, but amazingly, it's the least important part on the front wing."

Hamilton passed Charles Leclerc for a famous victory – his eighth at his home race – with two laps to go.

"From our planners' view in the race, who were forecasting it live, we were looking at catching [Leclerc] up with two laps to go," added Shovlin.

"When we thought it was on I'd say was five laps into that [push]. You normally see the drop on the tyres, but you could just see Lewis holding this eight-tenths advantage to Charles every lap.

"And to be honest with Lewis, you can hear it in his voice and in what he's saying on the radio; you just get this switch where he knows in his head he's going to do it."

FIA race director Michael Masi – who was bombarded on radio with messages from Mercedes and Red Bull stating their case during the controversy – felt the stewards had got Hamilton's penalty right.

Masi insisted the severity of any crash, an injury to a driver or the race situation are factors that cannot be taken into account when applying punishments.

"Looking at the incident, I agree with the stewards and the penalty they applied," Masi said.

"I think the wording was clear as per the regulations, [Hamilton] was 'predominantly to blame', not 'wholly to blame' for it.

"He could have tucked in further like what happened with Charles later on and that may have changed the outcome, but we don't know – we have to judge on the incident itself.

"One of the big parts [of stewarding] that has been a mainstay for many, many years [is] that you should not consider the consequences in an incident.

"So when you judge incidents, they judge the incident itself, the merits of the incident and not what happens after as a consequence.

"The stewards have been advised to do from the top down – and I'm talking team involvement and so forth.

"That's the way the stewards judge it, because if you start taking consequences into it, there are so many variables rather than judging the incident itself."