Ronaldo is bad for my career, says United winger

Martin is 21 today and determined to win a permanent move to Sheffield United that could depend on him helping to remove the pressure on beleaguered boss Bryan Robson.

But the winger revealed last night that he is committed to breaking out of Old Trafford whatever happens.

'At 21 it's time to look at yourself and ask if it's ever going to happen at Manchester United,' said Martin ahead of a Bramall Lane game with struggling Scunthorpe which could prove critical for Robson.

'I've taken a lot of knock backs there over the years which could make me stronger or set me back.

'I've learned a lot in my time with United, improving greatly by training with world-class players. But I'm realistic and feel I might need to move on now. You need to get out while you're young. I've been around the first team for the past two years but only made two appearances.'

But Martin admits he must recapture the form of an impressive spell with Plymouth earlier this season to convert a similar loan with United into a contract offer.

'My ideal birthday present would be to score the winner against Scunthorpe,' he said.

'I don't feel I've set the world on fire so far and there's more to come. I see myself as a direct, pacy winger who can score goals.'

And Martin is convinced the Blades have the talent to be nearer the top of the table, adding: 'We've got the players on paper to be at the top and we should be.'