The Canada striker buried a 50th-minute header in a match Norwich knew would see them guarantee second place with one regular-season match remaining after the Welsh side fluffed their lines in a 3-0 home defeat to Middlesbrough.

With Queens Park Rangers champions - FA inquiry permitting - Norwich took the last automatic promotion place, moving four points clear of Cardiff, who suffered the agony of play-off final defeat to Blackpool last season.

It is a remarkable achievement for Canaries boss Paul Lambert, a second successive promotion for a side that lost 7-1 to his Colchester United side days before the Scot took over at Carrow Road in August 2009.

It is also Norwich’s third spell in the top flight during the Premier League era, their last season at that level culminating in relegation six years ago.

In a first-half that saw Norwich claim more possession and fashion the better chances, both sides were well organised as the biggest threats came from set-pieces.

Zak Whitbread somehow headed wide in the second minute when found unmarked by David Fox’s ball, while defensive partner Elliott Ward missed a similar if less straightforward chance on 35 minutes.

Pompey defenders Hermann Hreidarsson and Aaron Mokoena were both fortunate not to be sent off for a pair of reckless challenges, with Mokoena’s on Jackson particularly bad while the Icelander had a little kick at Grant Holt after his foul.

Mokoena was the only thing that stood between Holt and a wonder goal too, the South African clearing off the line after the Norwich striker set himself up with a brilliant spinning flick.

Despite having nothing to play for, mid-table Pompey were not bad either, Dave Nugent and Nwankwo Kanu bright on the break and Greg Halford’s renowned long throw asking questions of the visitors: Paul Tierney was also lucky to escape a penalty claim when the ball appeared to hit his hand in the box.

It was goalless into the break but that changed soon afterwards as Norwich came out like a team who had just been told they would be mixing it with the likes of Manchester United, Chelsea, Arsenal, Manchester City and Liverpool if they could just get a goal.

Jackson missed a gilt-edged opportunity, mis-hitting his finish wide after Holt’s superb flick played him in down the left, but the in-form striker made amends soon afterwards.

After some lovely off-the-ball movement by Holt and Wes Hoolahan, Jackson stole in at the far post to head Fox’s excellent cross across Jamie Ashdown and inside the far post, his 14th league goal of the season.

It was a deserved goal and prompted Pompey to make a game of it, Nugent and Jonathan Hogg denied by Canaries keeper John Ruddy and his centre-half Ward.

Things had opened up though, and Norwich went close to a second when Russell Martin was kept out by Ashdown, while Halford did well to deny Jackson after Tierney’s great run and cross.

Dean Surman had a fizzing half-volley deflected wide by Mokoena’s good block, and with 23 minutes left Norwich were happy to slow the game down and shut up shop as the top flight beckoned.

And they closed the latter stages out, the 3,000 away contingent celebrating wildly with majority shareholder Delia Smith as they returned to the Premier League.