Jim Culloty is out to prove himself number one when he continues his partnership with Edredon Bleu on his first ride in the £125,000 Pertemps King George VI Chase at Kempton on Boxing Day.

Tony McCoy has been teaming up with the champion two-miler when available but Culloty is back in the frame thanks to a third successive victory on Edredon Bleu in the Peterborough Chase at Huntingdon last month.

The Irishman got the nod from owner Jim Lewis and trainer Henrietta Knight for the mid-season three-mile championship even though it is likely that the champion jockey will be available.

''I was told soon after Huntingdon that I'd got the ride at Kempton,'' said Culloty.

The rider, who was 27 on Monday, was establishing himself as Edredon Bleu's regular partner with two successive victories when an injury forced him to miss out at Sandown in February, 1998.

McCoy stepped in to score and repeated the trick in the Grand Annual Chase at Cheltenham the following month.

Since then McCoy has ridden Edredon Bleu when available, including two more appearances at the Cheltenham Festival, resulting in second spot in the 1999 Queen Mother Chase before going one better in the two-mile championship last March.

After winning on Edredon Bleu in the 1999 Peterborough Chase, Culloty did not ride him again until the same race 12 months later, even though he has a 50 per cent strike rate with five wins from ten starts.

He has had to take the situation on the chin, be patient and wait for his big chance. That comes now.

''It's a big opportunity for me and if he won it would be a great opportunity,'' Culloty said.

It is a massive test for both horse and jockey as the two-mile king is moving up in trip to be pitched against the cream of the staying chasers, headed by See More Business, the dual King George winner and 1999 Cheltenham Gold Cup hero.

''I rode Edredon Bleu to beat Kadi over two-and-a-half miles at Kempton in 1997 and he only just scraped home.

"But that was on bottomless ground and he's a lot stronger now,'' said Culloty.

''He certainly got two-and-a-half very well the last time. Kempton is a big, galloping track, so I wouldn't say it was going to be an easy three miles and it's going to be a competitive race.

''They'll no doubt go a gallop and he will have to get the three miles properly.

''If there's any doubt in him getting the trip that race will find him out and at least we'll know for the future.''

Culloty, who came to England from Killarney at the age of 18, rode his first winner as an amateur in an Exeter bumper in 1994 and is in his sixth season riding for Knight at Wantage.

As for big-race tactics, Culloty remarked: ''The same as usual I'd say, making the running on him. He usually runs his races from the front although I'd have to discuss it with the trainer first.''

Culloty cannot wait for Boxing Day, saying: ''I am really looking forward to it.

''See More Business is an obvious danger but the way Francois Doumen's horses won at Ascot I might have to worry about First Gold as well.

''And Legal Right gave a very impressive performance off 12st at Ascot on bad ground.''

Desert Orchid managed to step up from two to three miles when springing a 16-1 surprise in the 1986 renewal for the first of his record four wins in the race.

And at 12-1 with Ladbrokes, Edredon Bleu could prove an attractive each-way proposition to bridge the distance gap in the Christmas spectacular.

l Function Dream is set to step up in class at Wetherby on Boxing Day in the £35,000 Castleford Chase.

The Mary Reveley-trained mare was one of five horses declared yesterday for the Grade Two limited chase.

The eight-year-old has won her last two races, both at the West Yorkshire course, in fine style, leaping up the handicap to a rating of 144 as a result.

But she faces a stiff task against Direct Route, re-routed from the Pertemps King George VI Chase at Kempton, recent Ascot winner Celibate, last year's runner-up Aghawadda Gold and the progressive Davoski.

''It's a good race - you could finish last in it and have run well,'' Reveley said yesterday.

''It's been forced on us but she likes soft ground, she jumps well and you've got to try.

''She seems fine and I just hope she runs well.''

Function Dream also holds an entry in the Victor Chandler Chase at Ascot next month and Reveley added: ''We'll see how we get on before we think about that.''

l Trainer Howard Johnson has pulled his stable star Direct Route out of the Pertemps King George VI Chase at Kempton on Boxing Day.

The gelding, who prefers top of the ground, has been declared instead for the Castleford Chase at Wetherby the same day where he heads the weights on 11st 10lb.

But Johnson has warned that he might withdraw the gelding if he is not happy with ground conditions at the West Yorkshire course.