NO horse has won successive Grand Nationals since the great Red Rum in 1973-74, but last year's hero Party Politics appears next in line to rectify matters in the world's greatest steeplechase today. Victory would propel the gelding's talented partner Carl Llewellyn to the very top rungs of his hazardous profession, alongside such household names as Peter Scudamore and Richard Dunwoody. And it would also carve out a special niche for Nick Gaselee, thequietly-spoken, gentlemanly trainer from Upper Lambourn, who once attempted, rather unsuccessfully, to guide the heir to the throne to riding glory on the Turf. The story of Party Politics is already bordering on the extraordinary, so why should it all stop now? Bought for a big, undisclosed sum, on the eve of last year's National, he carried the purple and pink colours of Mrs Pat Thompson to a thrilling win bytwo-and-a-half lengths over Romany King. Over four-and-a-half miles (7,200 metres), with 30 fences of all shapes and sizes to be jumped, Party Politics was in his element. Standing nearly 18 hands tall - you would need a stepladder to see over his back - he tackled some of the fearsome fences as if they were mere brush hurdles. He was like an ambling,agile 7 foot, 6 inch basketballer, with leaping power to match. This year, it has all been very different. Party Politics' first two outings resulted in the gelding being twice pulled up, and on the second occasion he reportedly bled. But a transformation was about to take place, as Gaselee and the vets decided that the real problem was that Party Politics could not get his breath. So, for the second time in his career, the gelding underwent an operation on his wind, with a tube being inserted in his neck and a hole, to allow air to flow more freely, fully visible. Suddenly, Party Politics was a new horse, showing staggering improvement when romping home the four-length winner of the Greenalls Gold Cup at Haydock Park at the end of February. Llewellyn reported: ''Since the operation, Party Politics makes a hell of a noise when he's racing. But it certainly doesn't seem to worry him, and judging by his Haydock performance, his breathing is fine. ''Now that he can catch his breath again, he is going to be very difficult to beat. He jumped brilliantly last year, making nothing of those big fences,'' his level-headed pilot added. Apart from Party Politics and his breathing, Llewellyn has had troubles of his own. He suffered a broken left collarbone when brought down on the promising hurdler Andrew's First at Cheltenham last month, and only returned to the saddle on Wednesday, when his first ride back, Sweet Duke, was a winner at Ascot. ''That was a pretty good test as Sweet Duke was pulling a bit and if my injury was a worry I would have felt it. Instead, it felt fine. I have four or five hurdle rides lined up but the National will be my first ride back over fences,'' he explained. I believe that Party Politics could be a real Aintree specialist. Sure, he is asked to carry nine pounds more than when he won last year, but he is not harshly treated when you consider that Red Rum rocketed 23 pounds up the weights after beating Crisp in the epic 1973 running. Red Rum, of course, went on to win a third Grand National in 1977, but Party Politics and his connections can worry about that in 1994. As for dangers, I see the chief one being Peter Scudamore's mount Captain Dibble, a real staying prospect who has already won the Scottish National, new favourite Zeta's Lad, who haswon five races in succession this year, and Royal Athlete, who has been at the head of the market ever since his fine third to Jodami and Rushing Wild in the Cheltenham Gold Cup. Scudamore will be having his 13th Grand National ride, and Captain Dibble, who has greatly pleased his trainer Nigel Twiston-Davies, would rank as one of the very best of them. What the reigning champion jockey will not want is to see one of the horses he rejected - four are trained by Martin Pipe - sailing home down the outside toland the major prize. Of this brigade, Chatam is the one to fear. He did not jump at all well at Cheltenham after a bad mistake at the first fence last time, bu