Born and raised in Worcester, Mark grew up listening to his father's stories of his time as a senior NCO in the Royal Military Police. A career in the British Army was all Mark ever aspired to, and he presented himself to the local Armed Forces Careers Office the day he received his A-level results, aiming to follow in his father's footsteps as a Redcap.
Phase 1 Training at the Army Training Regiment in Winchester was followed by Phase 2 training at the Defence College of Policing and Guarding, where he graduated second in his class. Promoted on completion of training to Lance Corporal, Mark was posted to 1st Military Police Brigade, 1 Regiment RMP, 150 Provost Company at Catterick in Yorkshire.
He developed a reputation as a shrewd and logical MP, and would have been fast-tracked into training for the Special Investigation Branch had his unit not been deployed to Iraq as part of Operation Telic.
Mark's deployment in Iraq was uneventful, consisting mostly of policing bored and frustrated soldiers. On his return to the UK Mark was promoted to Corporal, but spent little time adjusting to his new duties before being deployed again, this time as part of Operation Herrick in Afghanistan.
The Afghan desert became Mark Castle's crucible, forging him from a competent MP into a hardened soldier with a desire to do even more for his country. He repeatedly came under enemy fire during reconnaissance patrols in Helmand province, and was travelling as part of a convoy that was struck by American missiles in a friendly fire incident.
His most harrowing experience came while acting as a close protection detail leader for a visiting senior officer. As the convoy returned to their FOB, the vehicles were ambushed by a sizable enemy force. Able to call in friendly support and hold their position against a numerically superior force, Mark was able to evacuate his principle safely. He was not, however, able to save all of his colleagues, and two of his closest friends did not survive the firefight. During debrief it transpired that human intelligence sources had learned of the ambush plan two days previously, but the message had not been passed on to Mark or his team.
Promoted to Sergeant, and with feelings of loss and helplessness driving him on, Mark returned to the UK for a secondment with 1st Intelligence Surveillance and Reconnaissance Brigade, 1 Military Intelligence Battalion at Catterick. There he learned how intelligence and military police interests could work together to maximise the effectiveness of intelligence passed to troops on the ground, with a view to avoiding the sort of ambush that cost Mark his friends.
This new determination to better himself, and better the Army's intelligence-gathering capabilities, led to Mark's application to UK Special Forces Selection to join the secretive Special Reconnaissance Regiment. If his deployment in Afghanistan made him a stronger and sharper MP, Selection reforged Mark into a robust, focused and dedicated soldier, prepared to do whatever was needed to ensure the success of his mission and prevent the senseless loss of any more lives due to lack of intelligence.
Passing out of Selection with his emerald-grey beret and midnight blue stable belt, Mark joined SRR and it's missions in covert surveillance, clandestine reconnaissance and tactical counter-terrorism. During the five years he served with SRR Mark was involved in numerous highly classified operations, including a joint SRR-SAS operation to find and retrieve a lost Soviet nuclear missile warhead before it hit the arms black markets of the Middle East.
Distinguishing himself as a perceptive and reliable NCO, even in the most gruelling of conditions, Mark was surprised to find himself recommended by his CO for secondment from SRR to the newly formed Five Eyes Special Tactical Assault Regiment. Though few details about the unit were available, Mark was keen to broaden his experience and put his skills to use in an international setting.
