Jonny Wilkinson was last night undergoing X-rays to determine the extent of the shoulder injury he aggravated in Newcastle's 23-19 Zurich Premiership win over Northampton.

The 24-year-old fly-half suffered a recurrence of the injury on his first appearance since landing the drop goal which won the World Cup for England five weeks ago .

Wilkinson's latest setback comes seven weeks before England begin the defence of their Six Nations crown against Italy in Rome.

Director of rugby Rob Andrew. said: ''He's going for X-rays to determine the extent of the injury.

''His arm and shoulder are sore but he's fine. It's frustrating but we've just got to deal with facts when we've got them, there is no point in speculating.''

Wilkinson was due to make his first Newcastle appearance of the season a fortnight ago but was forced to delay his return.

Andrew defended his decision to bring back his star player, insisting there was no medical barrier to his comeback.

''He wouldn't have played if he was not right to play,'' he said. ''He even had another X-ray yesterday to make sure he was alright.''

Wilkinson, playing his 99th Premiership match, had kicked three penalties from as many attempts with the help of the wind to give Newcastle a 9-6 lead, but Northampton struck after 44 minutes through captain John Leslie. The former Newcastle centre's try put the visitors 13-9 in front.

The Falcons' cause began to look hopeless when Wilkinson went off but replacement Dave Walder played a key role in their fightback in the final quarter.

He converted a controversial try by winger Michael Stephenson and clinched victory by intercepting Nick Beal's pass and racing 80 metres for a glorious touchdown, to which he added his second goal.

''I thought we played brilliantly,'' said Andrew. ''It was the best we played all season in the first half. All that was missing was a couple of tries. I thought the character of the team really came through when we lost Jonny.''

The injury to Wilkinson overshadowed the controversy over Newcastle's first try, with Saints winger Bruce Reihana insisting he had touched down a kick from Newcastle hooker Matt Thompson before Stephenson followed up to claim the score.

''I definitely got downward pressure on it,'' said Reihana. ''It's something you've got to take.''

Northampton missed the chance to go third in the table and have now lost five successive away matches in all competitions but coach Wayne Smith was delighted with his team's performance.

''It's disappointing to lose a game in those circumstances,'' he said. ''It was a game we should have won. We gave them two tries when they never looked like scoring any.''

Wilkinson went down in a heap near the touchline after 53 minutes after attempting a tackle on Reihana. He had treatment on his neck and shoulder for four minutes before finally getting to his feet.

There was no way he could continue and the fly-half looked a disconsolate figure as he was helped off the field.

Wilkinson only discovered he was making his eagerly-awaited return 45 minutes before kick-off when referee Ashley Rowden declared the Kingston Park pitch fit after a severe overnight frost.

That was a big relief to the capacity 10,000 crowd, who were desperate to see their favourite in action.

Wilkinson showed no sign of the fractured shoulder facet that delayed his comeback as he kicked the Falcons into a 9-6 interval lead with three crisply-struck penalties.

Northampton, who were without two of their World Cup heroes in Ben Cohen and Matt Dawson, kept in touch with penalties from Shane Drahm and Reihana.

They went in front for the first time four minutes into the second half when Leslie took Drahm's well-timed pass to finish off a period of sustained pressure with the first try of the match.

Drahm's successful conversion made it 13-9 and the visitors then brought on England hooker Steve Thompson to give them more impetus.

Newcastle's plight looked increasingly desperate when Wilkinson went off but they regained the lead with two tries in three minutes.

The ever-dangerous Stephenson, who made two breaks in the first half, followed up Thompson's kick to secure the vital touch.

Walder landed the conversion then came up with his 80-metre interception try.

His second conversion made it 23-13 but two late penalties from replacement fly-half Paul Grayson kept the outcome in the balance to the end.

* England coach Clive Woodward's well-earned Christmas skiing holiday in Switzerland will have been soured by news that centre Mike Tindall will miss the entire 2004 Six Nations.

Woodward asked to be updated after Tindall sustained a serious ankle injury while scoring the first try during Bath's 24-15 Zurich Premiership victory over Saracens on Saturday.

Initial fears that the 25-year-old back had broken his leg were allayed by an X-ray which revealed no break, but an MRI scan at the Royal Bath United Hospital uncovered extensive tissue damage.

Tindall has ruptured all three of the lateral ligaments in his right ankle and must undergo an operation this week before embarking on a 12-week rehabilitation programme which will force him to sit out England's Grand Slam defence.

''It is a great shame for Mike. Ligament damage is often worse than a break,'' said Bath coach John Connolly.

''We initially thought he had broken his leg and we did hear a crack. He thought he'd broken it because he was in so much pain.

''He was bending down to pick the ball up when he got hit by a tackle. Then he twisted and he knew something was wrong."

Tindall's absence will be a bitter blow to Bath, who are already stretched in midfield with Mike Catt and Robbie Fleck in the treatment room, and he could potentially miss 11 matches for the Premiership leaders - including the crunch showdown against Wasps.

It robs Woodward of one of England's most solid performers and a player who would have been a certain starter in the Six Nations.