UPDATE: Subsequent stewards enquiry in favour of Mercedes, Lewis Hamilton keeps his win. Result stands.

Lewis Hamilton's win in the Italian Grand Prix could yet be under threat after Mercedes was called to the stewards to explain why tyre pressures on his and Nico Rosberg's car were too low.

On a weekend dominated by Pirelli tyres and the introduction of new tyre pressure guidelines, technical delegates sampled the tyres of Mercedes and Ferrari, with both Hamilton and Rosberg found to be 0.3psi and 1.1psi too low respectively.

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Stewards have subsequently summoned Mercedes representatives to explain, with penalties potentially to be levied to Hamilton.

"On the grid and after the five minutes signal the tyre starting pressure and tread surface temperature of the left hand side rear tyre was checked on car numbers 44, 06, 05 and 07 and were compared to the specifications of the official F1 tyre supplier. (19.5psi)

"The measured minimum tyre pressure of the left hand side rear tyre on car 44 was 0.3psi below the specified minimum tyre starting pressure and the measure minimum tyre pressure of car 06 was 1.1psi.

The revelation explains why Hamilton was asked to push in the closing stages of the Italian Grand Prix in anticipation of a possible time penalty being applied.

This penalty could be 25secs, which if this proves correct, means Hamilton keeps his win over Sebastian Vettel by just 0.042s. However, it could prove more lenient or indeed harsher.

Ferrari was given the all-clear.

More to follow