It's the lucrative endurance test that attracts hundreds of millions of viewers around the world.

First run in 1836, the Grand National is the most valuable jumps race in Europe - the prize pot is £1,000,000, including £561k for the winner.

At 5.15pm, 40 horses will tackle the 4 mile 2.5f Aintree course, which has been toned down from its infamously challenging peak. 

Three horses died either during or after the race in 1998 but fortunately there have been no fatalities since Synchronised in 2012.

However, two horses - Forest Des Aigles and Crucial Role - were fatally injured at the Festival meeting on Friday .

Kerryman Tommy Stack steers Red Rum to a third National win in 1977

It has been a long wait since 1974 and Red Rum for a repeat winner of the National, and it just goes to show how hard a race it is to win twice.

Nevertheless, Gordon Elliott's Tiger Roll looked like he might have gone close in the Gold Cup, so easily did he win the Cross Country at Cheltenham, and if he avoids trouble he is surely the one to beat.

In any other year Rathvinden would be heading the market and he can give the favourite most to do. At bigger prices, Regal Encore and Jury Duty look the ones for each-way backers.

It's a handicap rather than a Graded race, with Anibale Fly heading the weights at 11 stone 10lbs all the way down to Joe Farrell at 10-2. There are 19 Irish runners in the field.

1. ANIBALE FLY (Tony Martin) 7 (prospects out of 10)
Jockey: TBC after Barry Gerahgty's broken leg
Age: 9 | Weight: 11-10 
Third in the Gold Cup and fourth in the National last season. Lightly-raced this term, but looks equally as good after his runner-up finish at Cheltenham three weeks ago. Less time to recover this time and burdened with top-weight. 

2. VALTOR (Nicky Henderson) 3
Jockey: Daryl Jacob
Age: 10 | Weight: 11-6
For all he has achieved, Nicky Henderson has a poor National record and this French import is unlikely to improve it. Arguably his chance was blown when winning at Ascot by eight lengths, causing a 12lb rise in the weights.

3. TIGER ROLL (Gordon Elliott) 10
Jockey: Davy Russell
Age: 9 | Weight: 11-05
It has been a long time since a previous winner returned with stronger claims 12 months on, but this one does. Won a Grade Two hurdle over an inadequate trip before bolting up at Cheltenham. History awaits?

4. OUTLANDER (Gordon Elliott) 5
Jockey: James Bowen
Age: 11 | Weight: 11-04
A one-time top-class performer, his best days appear behind him and he has not come close to reproducing his old form this season. Could be one who the fences might spark back to life, however.

5. DON POLI (Phil Kirby) 4
Jockey: Patrick Mullins
Age: 10 | Weight: 11-03
Another from the yard who is a shadow of former years. This dual Cheltenham Festival winner always appealed as a National type, but since returning from a lengthy absence he has not looked in love with the game. Was transferred from Gordon Elliott to Phil Kirby on Wednesday after Darren Yeats bought him from Gigginstown.

6. GO CONQUER  (Nigel Twiston-Davies) 8
Jockey: Sam Twiston-Davies
Age: 10 | Weight: 11-03
Ultra-consistent chaser who excels on flat tracks and jumps brilliantly. A 6lb rise for his recent win makes life tougher, but the main question he has to answer is stamina. Likely to give his backers a good run for their money.

7. MALA BEACH (Gordon Elliott) 7
Jockey: Jamie Codd
Age: 11 | Weight: 11-02
Seems best suited to big-field handicaps, having won the Troytown and finished second in the Thyestes, so that is in his favour. Certainly no forlorn hope, but now an 11-year-old.

8. MINELLA ROCCO (Jonjo O'Neill) 5
Jockey: Richie McLernon
Age: 9 | Weight: 11-01
Represents connections who have tasted success in the National before and had the class to be second in the Gold Cup a few years ago. Has struggled since and little encouragement came from his Cheltenham run when pulled up.

9. LAKE VIEW LAD (Nick Alexander) 8
Jockey: Henry Brooke
Age: 9 | Weight: 11-01
Arguably comes here in just as good form as Tiger Roll, having won the Rehearsal Chase and Rowland Meyrick this season. Very fine third at Cheltenham also means he is 3lb 'well in', and he looks sure to be involved.

10. PLEASANT COMPANY (Willie Mullins) 6
Jockey: Paul Townend
Age: 11 | Weight: 11-01
Last year's runner-up, but the feeling is that was his big chance. Only had two runs this season and hard to take any encouragement from either. Banking on the 'Aintree factor' bringing him back to life.

11. BALLYOPTIC (Nigel Twiston-Davies) 6
Jockey: Tom Bellamy
Age: 9 | Weight: 11-01
Proper stayer who was beaten just a nose in the Scottish National last April. Fell on his first try over these fences in the Becher Chase, ran a fine race to be sixth in the Welsh National but then pulled up most recently at Haydock.

12. DOUNIKOS (Gordon Elliott) 7
Jockey: Jack Kennedy
Age: 8 | Weight: 11
Looks one of the more likely contenders from his trainer's huge army. Appeared to have lost his way before bouncing back to win last time out over three and a half miles. Marathon trips could be the making of him.

Rathvinden

13. RATHVINDEN (Willie Mullins) 9
Jockey: Ruby Walsh
Age: 11 | Weight: 11
In any other year he would be a short-priced favourite, but Tiger Roll stands in his way. Won the four-miler at Cheltenham last year, proving his stamina, and took Ireland's most notable trial for this recently. Huge player.

14. ONE FOR ARTHUR (Lucinda Russell) 6
Jockey: Derek Fox
Age: 10 | Weight: 11
Famously struck gold two years ago, but nothing has gone right for him since. He missed the following season through injury and has been restricted to just two runs this term because of the weather, unseating in both.

15. ROCK THE KASBAH (Philip Hobbs) 7
Jockey: Richard Johnson
Age: 9 | Weight: 10-13
Will he finally deliver champion jockey Richard Johnson a first National? Certainly not without a chance, because he is a good jumper who races prominently. Just a worry the handicapper may have hold of him.

16. WARRIORS TALE (Paul Nicholls) 3
Jockey: Harry Cobden
Age: 10 | Weight: 10-13
Trainer has been working miracles all season, but this would top them all. While the 10-year-old has run over the fences before, winning the Grand Sefton, he looked a blatant non-stayer 12 months ago.

17. REGAL ENCORE (Anthony Honeyball) 7
Jockey: Mark Walsh
Age: 11 | Weight: 10-12
Those looking for one at a big price could do worse. Eighth two years ago, he has been lightly-raced since, but finished third in the Ladbrokes Trophy and won a big pot at Ascot. Nice prep last time out.

18. MAGIC OF LIGHT (Jessica Harrington) 5
Jockey: Paddy Kennedy
 Age: 8 | Weight: 10-11
Made hay in mares' races on both sides of the Irish Sea this season, over both hurdles and fences. Fair seventh at Cheltenham, but does not run like one who wants this trip.

19. A TOI PHIL (Gordon Elliott) 4
Jockey: Denis O'Regan
Age: 9 | Weight: 10-11
Decent two-and-a-half-miler at his best, but had been disappointing this season until going close in a hot Cheltenham handicap last time out over hurdles.

Robbie Power

20. JURY DUTY (Gordon Elliott) 8
Jockey: Robbie Power
Age: 8 | Weight: 10-11
Winner of the American Grand National, although that is only over two miles and five furlongs and hurdles. Classy novice last season and good win last time out. Not to be underestimated.

21. NOBLE ENDEAVOR (Gordon Elliott) 6
Jockey: Mark Enright
Age: 10 Weight: 10-10
Had looked an ideal type for this race a couple of years ago, but injury has intervened. Ninth in the Becher gave him a taste of the fences and mid-division at Cheltenham. No forlorn hope.

22. MONBEG NOTORIOUS (Gordon Elliott) 6
Jockey: Sean Bowen
Age: 8 | Weight: 10-10
Yet another for these connections, he has always looked suited by a real test of stamina. Eighth when well fancied for last year's Irish National, he has struggled on quicker ground this term - so any rain would be a plus.

23. RAMSES DE TEILLEE (David Pipe) 7
Jockey: David Noonan
Age: 7 | Weight: 10-9
Has always been viewed as next year's horse, but made startling progress this year so connections have had their hands somewhat forced. Narrowly missed out to Elegant Escape in Welsh National, but another who needs the mud flying.

24. TEA FOR TWO (Nick Williams) 4
Jockey: Lizzie Kelly
Age: 10 | Weight: 10-9
Another who would be front-page news if he won because he is ridden by Lizzie Kelly and was the horse to help her create history a few years ago in a Grade One at Kempton. Unfortunately, he has not come close to reproducing that form for a while.

26. STEP BACK (Mark Bradstock) 6
Jockey: Nico de Boinville
Age: 9 | Weight: 10-7
An intriguing contender from the Coneygree team. Showed his ability when a wide-margin winner of the bet365 Gold Cup. This has been the plan all along, but he has only had two runs since Sandown - and down the field in both.

27. ULTRAGOLD (Colin Tizzard) 5
Jockey: Tom O'Brien
Age: 11 | Weight: 10-7
A real specialist over these fences, but all his good runs have come over shorter trips. His third in the Becher offered hope, but he was pulled up at Cheltenham behind Tiger Roll.

28. BLOW BY BLOW (Gordon Elliott) 3
Jockey: Andrew Ring
Age: 8 Weight: 10-6
Well placed to win first time out this season, but has shown absolutely nothing to recommend him since.

29. UP FOR REVIEW (Willie Mullins) 7
Jockey: Danny Mullins
Age: 10 | Weight: 10-6
Has always looked the type to pick up a nice race, and his third in the Thyestes promised plenty. Was travelling well at Cheltenham until a big blunder cost him any chance. That has to be a worry where these fences are concerned.

30. SINGLEFARMPAYMENT (Tom George) 4
Jockey: Paddy Brennan
Age: 9 | Weight: 10-6
It would be a fair achievement if this notoriously weak finisher can win the National. Has looked sure to oblige on a number of occasions only to raise the white flag close home. Ability not in doubt.

31. VIEUX LION ROUGE (David Pipe) 5
Jockey: Tom Scudamore
Age: 10 | Weight: 10-6
Looks like his best chance to win is behind him. Seventh, sixth and ninth the last three years, he has won the Becher - but recent form does not suggest he is improving.

Rachael Blackmore

32. VALSEUR LIDO (Henry de Bromhead) 4
Jockey: Rachael Blackmore
Age: 10 Weight: 10-6
Another who appears to have lost his way. Once a very smart chaser, he was eighth last year but is very hard to recommend on recent form.

33. VINTAGE CLOUDS (Sue Smith) 7
Jockey: Danny Cook
Age: 9 | Weight: 10-4
Jumps well, stays all day and represents a trainer who has won the National before - so plenty going for this grey, who bounced back to form at Cheltenham and was third in the Scottish National last year.

34. GENERAL PRINCIPLE (Gordon Elliott) 5
Jockey: J J Slevin
Age: 10 | Weight: 10-4
Won last year's Irish National in a blanket finish and had been running well enough to give him a squeak before an unlucky run at Cheltenham, where he made mistakes and met plenty of trouble, which was not an ideal prep.

35. LIVELOVELAUGH (Willie Mullins) 4
Jockey: David Mullins
Age: 9 | Weight: 10-4
Had the pace to finish second on fast ground over two and a half miles on his penultimate start and has never appealed as one crying out for this test.

36. WALK IN THE MILL (Robert Walford) 6
Jockey: James Best
Age: 9 | Weight: 10-4
Won the Becher Chase in good fashion and has been saved for this race. Has shown up well in a couple of runs over hurdles since then.

37. FOLSOM BLUE (Gordon Elliott) 5
Jockey: Luke Dempsey
Age: 12 | Weight: 10-4
Absolutely guaranteed to stay the trip, but can tend to get outpaced early on and could soon lose interest.

38. CAPTAIN REDBEARD (Stuart Coltherd) 3
Jockey: Sam Coltherd
Age: 10 | Weight: 10-3
Beat Gold Cup outsider Definitly Red in a match, for his small Borders stable, and ran well again on return to Kelso last month. Unseated early in last year's National, though, and otherwise unraced beyond a little over three miles.

39. BLESS THE WINGS (Gordon Elliott) 3
Jockey: Robbie Dunne
Age: 14 | Weight: 10-3
Defied his odds to finish third last year as a 13-year-old, but is another year older and his form has been getting progressively worse.

40. JOE FARRELL (Rebecca Curtis) 7
Jockey: Adam Wedge
Age: 10 | Weight: 10-2
Last year's Scottish Grand National winner should stay at least. He has had an interrupted campaign, after an early setback, but was much-improved after his belated reappearance when second at Newbury two weeks ago.

25 (Reserve). JUST A PAR (James Moffatt) 2
Jockey: Aidan Coleman
Age: 12 | Weight: 10-02
He has proved several times that he can handle these fences. But at 12, with just one run here in December for his new stable after a 20-month break, surely his best racing days are behind him.