By North-west correspondent Alex Stevens

Patrick Robert’s loan move to Celtic is on the verge of collapsing over the length of the deal.

The Scottish giants have threatened to pull out of the transfer unless the teenage winger is signed on an 18-month loan deal.

But City are only looking for Roberts, 18, to get first-team experience until the end of the season.

Football Insider revealed last week that the two clubs were in negotiations over a January deal for the England Under-19 international, who joined City from Championship club Fulham last summer for an initial £4.5million rising to £11million.

Celtic manager Ronny Deila insists he will not budge on the length of agreement he wants despite the strong relationship he personally has with the Premier League big-hitters.

He said: “We will not take a player on loan to have him only until the summer. He would have to be something special. If it’s going to be loans then it has to be longer than just to the summer.

“We have a relationship with Manchester City. It’s a relationship that I have had for many years, since Stromsgodset.

“We trust each other in the way that we have developed players for them and if they can bring quality into our squad — like we did with Jason Denayer and John Guidetti — then it is positive for both of us.

Celtic manager Ronny Deila is targeting Premier League talent in the January window

Loan ranger: Deila wants Roberts for 18 months

“But now we know if we’re going do to things like that, we have to have an arrangement that is over the summer and for a much longer period.

“If that is not the case it will not happen, you have my word on that.”

The teenager is regarded as one of the outstanding players in his age group in the country but has featured just once in the Premier League this season – a four-minute cameo in City’s 4-1 defeat at Tottenham in September.

Roberts has also twice appeared in the League Cup for City, coming on as a substitute in the victories over Sunderland and Crystal Palace.