Tom Clarkson emerges as Leinster's tighthead future as Furlong faces World Cup fitness race

Thomas Clarkson capped a transformative season by starting at tighthead as Leinster ended a three-year trophy drought, earning praise from captain Jack Conan after the province’s URC final victory at Aviva Stadium. With Tadhg Furlong battling to be fit for the Rugby World Cup, the question of who wears the number-three jersey for both Leinster and Ireland is no longer straightforward.

“Tommy was brilliant,” Conan told reporters post-match. “He was fantastic. You come up against the Bulls, who are renowned for their scrummaging, and he gave a great account of himself. He is someone that has grown immensely throughout the season and he is getting his just rewards for it — getting capped by Ireland, and everything else.”

Clarkson made 19 appearances for Leinster in 2024/25, including eight consecutive starts at tighthead. He also made his Ireland debut against Argentina, accumulated seven further Test caps, and received a late call-up to the British & Irish Lions touring squad after Furlong was ruled out through injury at the end of the club season.

The Lions addition came in characteristically unplanned fashion. Clarkson had scored his first try in a green jersey against Portugal — believing it to be his final game of the season — and was out with Ireland teammates when a message arrived from Lions head coach Andy Farrell asking him to make contact. A follow-up call from assistant coach Paul O’Connell made clear the urgency. Clarkson, along with Jamie George and Jamie Osborne, joined the touring squad as late additions and all three featured in the Lions’ victory over the First Nations & Pasifika XV. Farrell subsequently asked Clarkson to remain with the squad for the remainder of the tour and singled him out for praise after his Lions debut.

“It wasn’t a kind of ‘nepo’ selection if you’d call it that,” Clarkson said at the time. “I benefited from Tadhg being injured at the end of the season, but I’d like to think I took the opportunity.”

The rise has been steep. As recently as January 2024, Clarkson was playing club rugby for Blackrock in Division 1B of the All-Ireland League. He described himself in a recent Sunday Times interview as having been “small and weak” at 112kg during his underage years — he was part of Noel McNamara’s Ireland Under-20 side that won a Six Nations Grand Slam in 2019 — and has since added considerable bulk, now weighing in at around 125kg.

Clarkson’s story carries an additional international dimension. His full name is Tommaso Clarkson, and his mother Nina is originally from Casalattico, near Rome. Italy approached him to explore whether he would represent the Azzurri before he committed to Ireland.

He made his Leinster debut in August 2019 at the age of 19, but waited four years for his first Champions Cup appearance for the province. His emergence as a genuine first-choice tighthead — at a time when Furlong’s fitness remains uncertain ahead of the World Cup — marks one of the more significant positional shifts in Irish rugby heading into the next major tournament cycle.