The regiment was captured after severe fighting, but some batteries managed to escape after the Battle of Dunkirk.

The regiment reformed and was deployed to Northern Africa in late 1940, where it arrived with the Middle East Command in October 1940 and took a large part in Wavell's campaign which opened on 9 December 1940.

[3] 1 RHA then joined 10 Armoured Division in Aleppo and spent the next year training all over Syria, Palestine and the Suez Canal Zone.

[3] The regiment saw service as follows:[4] 1 RHA was stationed in Palestine after the Second World War, during the period of terrorist activity that led to the creation of the State of Israel.

[4][5] The regiment then deployed to Northern Ireland on Operation Banner three more times, Sep 72 - Jan 73 in Long Kesh, Mar - Jul 74 in Belfast (City Central), and Mar - Jun 76 Belfast (Grand Central/City Centre).

[4] When the Cold War ended in 1990, the Options for Change reforms were published, and the regiment ordered back to England within the next two years.

In September 1992, the regiment moved to Assaye Barracks, Tidworth, renamed as 1st Regiment Royal Horse Artillery and re-equipped with the L118 light gun in CRA, 3rd (United Kingdom) Mechanised Division in support of the 1st Mechanised Brigade.

[7] On 28 September 2004, a convoy of 1 RHA vehicles was ambushed, resulting in the loss of Cpl Marc Taylor REME and Gunner David Lawrence in an improvised explosive device attack.

[9] In September 2009 1 RHA deployed for approximately 7 months to Helmand province, Afghanistan on Operation HERRICK 11 supporting 11 Light Brigade.