Wallcroft

"Wallcroft, Griffen, cover our six."

- Captain Price's orders during Crew Expendable

Sergeant Wallcroft is an SAS soldier who serves alongside Soap, Price, and Gaz during the events of Call of Duty 4: Modern Warfare and Marcus Burns in Call of Duty: Modern Warfare 3.

Call of Duty 4: Modern Warfare
He is seen in the mission "Crew Expendable" in Call of Duty 4 guarding the ship deck along with Griffen.

Call of Duty: Modern Warfare 3
Wallcroft and Griffen reappear in the Modern Warfare 3 campaign mission, "Mind the Gap", as SAS squad leaders. Little else is known at this time.

Trivia

 * On the level "Crew Expendable", Wallcroft, Griffen, and the final SAS troop have plot armor. If he spawns in other levels, such as "Ultimatum" or "No Fighting In The War Room", he will be vulnerable like others.
 * At the start of "Crew Expendable", when you're on the helicopter, you'll see Wallcroft is not present. You can only see John Price, Gaz, Griffen, a randomly generated SAS soldier, and the two pilots. However, he will instantly spawn opposite where the randomly generated SAS soldier was sitting (between Griffen and Gaz), once Soap, Price and the SAS soldier have rappelled down.
 * A Private Wallcroft can randomly spawn on any SAS level, including "Ultimatum" and in the end of "One Shot, One Kill". Also on "Crew Expendable", there are rarely two SAS men both named Wallcroft. One appears as a Sergeant, while the other is a Private.
 * GTTV's episode of Modern Warfare 3 confirms that Wallcroft is not only in fact the squad leader of Marcus Burns' squad, but is also voiced by Craig Fairbrass (who voiced Gaz and Ghost) making it the third character that Craig does the voice for in a Modern Warfare game.