Smalling's agent James Featherstone, who had earlier put a private jet on standby with the move still up in the air, posted a photo of the two of them holding a Roma jersey after the deal had been finalised.

Reports claimed Roma submitted the necessary paperwork to the Italian FA just 60 seconds before the deadline in what was a long-running saga to see Smalling earn a permanent return to Italy.   

Smalling had cut a frustrated figure around Carrington in recent weeks and many would argue, on the back of Sunday's performance against Tottenham, that he could still make a telling contribution to the first team.

The 30-year-old impressed on loan at Roma last season and, after Ole Gunnar Solskjaer failed to include him in his first-team plans this summer, made it clear he would prefer to return to Serie A where he can play regularly.

Smalling turns 31 next month and is under contract until 2022. He was forced out by Solskjaer last year when it became apparent he would not figure following Harry Maguire's signing and despite raised hopes ahead of this season, the picture remains the same.  

Despite having Victor Lindelof, Eric Bailly, Axel Tuanzebe Marcos Rojo and Phil Jones on their books, they want to add another centre back, albeit next year. Yet they are struggling to offload some of those players to make room and Roma's interest in Smalling remains the best chance of recouping substantial funds.

Smalling has been at United for 10 years and staff have been impressed by his professionalism as he continued to train twice a day, often on his own, up until last week. 

His representative Featherstone made necessary provisions for today by provisionally booking a plane to fly to Rome but with the Italian deadline closing at 7pm, time has been against them. In the end the deal was done at the final hour.