Armed to the teeth and sporting military fatigues and a combat helmet, the officer is part of a counter-terrorism unit unveiled at Wembley last night.
The elite Scotland Yard squad arrived in huge armoured vehicles to throw a ring of steel around the 80,000 fans watching England beat France.
The marksmen were also toting their new lightweight, semi-automatic SIG 516 rifle.
The 130-strong unit has been developing new tactics with UK special forces, including abseiling from helicopters and tackling rampaging gunmen.
They have been trained to shoot for the head instead of the usual target, the chest.
They came out of the shadows in the wake of the massacre of 129 people in Paris on Friday.
The heightened terror threat was confirmed last night when another friendly – between Germany and the Netherlands – was called off very late because of a ‘concrete’ bomb threat.
No risks were taken because three of the seven Paris suicide bombers had targeted a fixture at the Stade de France between France and Germany.
Last night’s match began with English and French fans uniting to sing France’s national anthem, La Marseillaise.
One expert described the counter-terrorism officers at Wembley as ‘effectively SAS officers in police uniform’.
Amid some of the tightest security ever seen at a sporting fixture, they took up key positions around the ground.
Many of the officers chose to cover their faces because they sometimes work undercover.