Lewis Hamilton takes a trip across the grass as he aborts his pit entry

Lewis Hamilton reflected on a "most emotional, unbelievable day" as he kept his German Grand Prix win after an investigation into a driving offence.

Hamilton cut across the grass to rejoin the track and take the lead after a late decision to abort a pit stop.

Stewards took into account mitigating factors in a chaotic part of the race and issued a reprimand.

"The most emotional day - up and down. No-one ever wants to go see the stewards," the Mercedes driver said.

F1 rules dictate that "crossing the line separating the pit entry and the track by a car entering the pit lane is prohibited".

Race stewards said that although Hamilton had clearly broken the rules on entering the pits, a reprimand was the "appropriate penalty". Other possible punishments included a five- or 10-second penalty.

The ruling took into account that the driver and team admitted their mistake; that the offence was during a safety car period, when the speed of cars on track is controlled; and that the manoeuvre did not endanger any other drivers and was "executed in a safe way".

His win gave him a 17-point championship lead over rival Sebastian Vettel.

Speaking after the verdict, Hamilton said: "It has been an unbelievable day."

Hamilton started the race 14th and had fought up to be fifth when a rain shower hit with just over 20 laps to go.

Vettel, who had dominated the race to that point, crashed and Hamilton took the lead as his rivals pitted following the subsequent safety car period.

Mercedes then called off a fight between him and team-mate Valtteri Bottas after the re-start, ordering the Finn to hold position to protect their unexpected one-two finish.

The result meant that, having expected to lose further ground in the championship to Vettel, Hamilton now has an advantage heading into next weekend's Hungarian Grand Prix, the last before F1's four-week summer break.

Speaking before the stewards' investigation, Hamilton said: "I don't remember feeling this great. I am going to try to enjoy it while it lasts. I am tired because it was a hard race.

"I saw the cloud coming and then it started to spit - and as soon as it started, I was like, 'Yes, this is going to create the opportunity at the right time.' And, Jeez, it did.

"It is a whirlwind of a season. It has been up and down. I am grateful for the ups and downs.

"I woke up this morning and I was like: 'I'm 14th, I don't know what I can do from there but the dream is to win.'

"We all have dreams and they just seem so impossible to reach but I have done it time and time again.

"I had this dream to win and I can't explain how it happened but I won. It gives me the confidence to know that when I go again at something, when I have a dream and a goal, I can get there with hard work."

The FIA's ruling in full

The stewards reviewed video and audio evidence, heard from the driver of car 44 (Lewis Hamilton) and the team representative. It was clear that there was an infringement of the above mentioned rule - the driver clearly crossed the line separating the pit entry from the track.

In deciding on the penalty for the infringement, we took into account the following mitigating factors.

i) The driver and the team candidly admitted the mistake and the fact that there was confusion within the team as to whether to stay out or to enter the pits and that led to the infringement.

ii) The fact that the infringement took place during a safety car period

iii) At no time was there any danger to any other competitor and the change in direction was executed in a safe way.