Pedro Marques said the place was safe but “obviously because of the kind of events” there had been an audit into safety conditions.

Two vehicles caught fire in the tunnel in a two-month period.

On 11 June 2017 a bus carrying 20 passengers caught fire and then a car went on fire on 8 August.

Nobody was hurt or injured in either case.

The tunnel was closed to traffic for different periods of time after the events.

The Marao connects Amarante to Vila Real in the north of Portugal. The 5,665-metre-long tunnel was opened in May 2016 and has two parallel tunnels with dual-carriageways