Officers have been granted powers to stop and search racegoers

Police have been granted powers to stop and search people within a four-mile radius of the circuit because of the failed attacks in London and Glasgow.

Officers are using section 44 of the Terrorism Act to carry out random vehicle searches and there are extra police inside the circuit.

There is no intelligence to suggest any threat to the F1 race at Silverstone.

We have upped security levels just because of concerns that there may be an incident and we want to reassure the public we are taking it seriously Supt Simon Blatchly

Racing fans have arrived in their thousands from all over the world to watch the first practice session.

Britain's Lewis Hamilton heads into his debut home Grand Prix at Silverstone this weekend with a 14-point lead in the F1 championship.

Supt Simon Blatchly said: "We have got additional security in place following the events in London and Glasgow, although there has been no direct threat to the British Grand Prix this year.

"We have upped security levels just because of concerns that there may be an incident and we want to reassure the public we are taking it seriously."