Fin Smith faces a pivotal practice session on Wednesday as England’s chief playmaker looks to prove his fitness for the autumn opener against Australia at Allianz Stadium.

Smith is to train alongside his international team-mates for the first time since injuring his calf in Northampton’s defeat by Leicester on 24 October.

England are increasingly optimistic the British and Irish Lion will prove he is ready for Sunday’s Nations Championship clash given he has so far progressed through every stage of his recovery.

Head coach Steve Borthwick names his team on Friday, potentially giving his first choice fly-half two full training sessions ahead of his hoped-for comeback in the first of four Tests this month.

Fin Smith has been England’s first choice fly-half since the last two rounds of the Six Nations (Adam Davy/PA)

If Smith fails to get the green light, Test centurion George Ford and Harlequins ringmaster Marcus Smith will compete for the number 10 jersey in a duel between experience and form.

“Fin is…