Lieutenant Colonel Hallatt joined the Army in Sept 1985. After qualifying to be a Bandmaster in 2000 he saw subsequent tours at the Lowland Band of the Scottish Division and The Life Guards. Operationally he was deployed for the war-fighting phase of the first Gulf War in Kuwait and Iraq working with the Chemical Weapons Early Warning Cell and Prisoner of War Tactical Questioning Team.
Lieutenant Colonel Hallatt was commissioned to become the SO3 Recruiting for the Corps of Army Music in 2007 following which he became Director of Music of the Band of The Royal Regiment of Scotland.
In September 2011, Lieutenant Colonel Hallatt was appointed as the last Director of Music of The Royal Artillery Woolwich Band and saw their departure from Woolwich after 252 years. He was operationally deployed on operations Afghanistan in support of Operation Herrick 19. After a short tour as Officer Commanding Training and Development, Lieutenant Colonel Hallatt was appointed to be the Director of Music the Band of the Household Cavalry.
As a keen composer, Lieutenant Colonel Hallatt’s crowning moment was to have his music performed at the Classic FM Live concert 2018 by the London Philharmonic Orchestra, multiple choirs and military musicians from all three services – resulting in a standing ovation! Lieutenant Colonel Hallatt has also had several CDs released; the most successful, Elegy, reached No.12 in the Classic Charts and more recently he has had his composition Balmoral Farewell peak at No.9 in the German Classical Charts. More recently his work Carolean Jubilate (Jubilation in the Age of King Charles III) composed to celebrate the coronation of their Majesties, King Charles III and Queen Camilla, was presented to the King and Queen in July 2024. The Iowa State University Wind Ensemble was the first group to perform this work in the United States.
In September 2018 Lieutenant Colonel Hallatt became the Chief Instructor at the Royal Military School of Music, Kneller Hall and played a pivotal role in the relocation of the school to Portsmouth in June 2021. His efforts resulted in him being awarded a Chief of the General Staff Commendation in the 2021 Birthday Honours List. He finally realised a boyhood dream in July 2021 becoming Director of Music of the Band of the Welsh Guards and after a short time with them promoted to Lieutenant Colonel to become the Principal Director of Music of the British Army and Commanding Officer of the Royal Military School of Music in May 2022.