He quickly proved his speed, competing for Ireland in the Karting World Championship in 2014 against the likes of Enaam Ahmed and Mick Schumacher.

[3] In January 2020 ALBIREX Racing announced that Allen would take part in the inaugural season of the Japanese Super Formula Lights series.

[4] However, due to COVID-19 travel restrictions Allen was unable to compete in the first three rounds of the championship at Motegi, Okayama and Sportsland SUGO.

[5] The Irishman made his series debut at Autopolis and scored a total of five points, helping him to finish 9th in the drivers' championship despite only participating in 3 rounds.

[7] Allen would eventually return to the Le Mans Cup in 2023, driving alongside James Sweetnam for Graff.