[2] Angus Fraser, Middlesex's managing director of cricket, said of Helm's 2+1⁄2-year contract deal: "Tom is an exciting young fast bowler and we are delighted to have him on board.

He is the fifth local boy we have signed in the past couple of years - Ravi Patel, Adam Rossington, Gurjit Sandhu and Ollie Wilkin are the others - and we hope that, along with these other cricketers, he will play a major role in Middlesex cricket in years to come.”[2]He made his List A debut against Yorkshire in June 2013.

In the summer of 2020, Helm was named in a 55-man group of players to begin training ahead of international fixtures starting in England following the COVID-19 pandemic.

[4][5] He was included in England's 24-man group for behind closed doors training for the One Day International (ODI) series against Ireland,[6][7] though he did not make the final squad.

In November 2020, he was named as a reserve player in England's squad for their series against South Africa.