The elite firearms officers pictured at the Met's mock terrorist attack staged in London today are kitted out with the latest high grade military gear.
The Met’s specialist firearms unit, SCO19, are among the more than 1,000 police officers and soldiers being deployed in the two-day training excerise.
Dubbed Operation Strong Tower, it is taking place today and tomorrow to test the response to a "marauding" Tunisia-style attack on the streets of London by terrorists carrying Kalashnikov's and other firearms.
Speaking about the equipment used by the armed officers, former SCO19 member Roger Gray said it has become increasingly powerful in order to deal with such threats, as fears of terrorism have increased.
In the photo, the two officers advance carefully upon their target with one standing slightly behind his partner, carrying an assault rifle in his arms.
The weapon is a SG 516, manufactured by global arms giant SIG Sauer, and used by the counter terrorist wing of SCO19.
Some 130 counter-terrorism specialist firearms officers (CTSFOs) are trained to use the rifles - and shoot to the head if necessary.
It weights 3kg to 3.5kg and is semi-automatic, 5.56mm assault rifle
The bullets fire at a high velocity and are said to be "extremely penetrative".
Both officers carry pistols in holsters strapped to their right legs.
The Met primarily uses the Austrian-manufactured Glock 17, a semi-automatic pistol which fires 9mm bullets rounds in a 17 round magazine.
Made from a plastic polymer, the gun is said to be lightweight, accurate and reliable.
The Glock weapon has a range of 50 metres, though is most effective at 10 to 25 metres.
The Ministry of Defence made the sidearm standard issue for the armed forces in 2013.
The officer leading the charge carries a bullet-proof shield while both are kitted out with solid helmets and body armour, which are kevlar reinforced.
Mr Gray, an author and former sergeant with the firearms branch, said: "The body armour is lined with Kevlar and the helmets are hardened with Kevlar.
"If confronting high velocity rounds, they will also have ceramic plates somewhere in the lining of the armour, in addition to the Kevlar itself. It's very heavy stuff to move about with."
The exercise is playing out under scorching temperatures, with 31C recorded in London today and up to 34C expected tomorrow, which Mr Gray said will make conditions "monstrously difficult" when armed officers are fully laden.
He said: "With any kind of prolonged containment, in these temperatures it's going to be quite unbearable.
"Take a 15 stone man, put all this stuff on him and you have a 20 stone man. They will be carrying 50 to 70 rounds of ammunition and that's all lead.
"You’ll only be able to sustain it for short period of time in reality, it's just too much weight. You would not be able to stand in these temperatures for long; they are going to find this monstrously difficult."