'I couldn't be happier' with Grand National champion Tiger Roll - trainer Elliott

Randox Health Grand National Venue: Aintree Racecourse Date: Saturday, 6 April Time: 17:15 BST Coverage: Live on BBC Radio 5 Live and the BBC Sport website - more details.

Hot favourite Tiger Roll will bid to become the first horse since the legendary Red Rum 45 years ago to win back-to-back runnings of the Grand National at Aintree on Saturday.

Bookmakers say £150m is set to be bet on the race's 172nd running, with many likely to back last year's winner.

Tiger Roll, who will again be ridden by jockey Davy Russell, heads a maximum field of 40 for the 17:15 BST race

His Irish trainer Gordon Elliott saddles a race-record 11 runners.

Tiger Roll's rivals will include Rathvinden, Anibale Fly, Vintage Clouds and Pleasant Company.

A year ago, Tiger Roll was the smallest horse in the field but successfully negotiated obstacles including Becher's Brook and The Chair under Russell, who was the oldest jockey in the race aged 39.

"He's one in a million really, he just have his own way of doing things. You just set the radar on where you are going and he perks up. Tiger Roll is a bit of a rock star," said Russell.

Tiger Roll is about 7-2 favourite for the four-and-a-quarter-mile race and if he triumphs again, could be the shortest-priced winner since Poethlyn (11-4) 100 years ago.

Approximate odds for the Grand National 7-2 Tiger Roll; 10-1 Rathvinden; 14-1 Anibale Fly, Vintage Clouds; Lake View Lad; 16-1 Rock The Kasbah; 20-1 Joe Farrell, Pleasant Company, Rock The Kasbah; 20-1 Jury Duty, Step Back; 25-1 bar

Other potential Grand National stories

Champion jockey Richard Johnson is riding in the race for a record 21st time, but has yet to win. He is on board Rock The Kasbah, whose name is a nod to the hit 1980s song by the Clash.

Could Trevor Hemmings become the first racehorse owner to have a fourth Grand National winner after victories with Hedgehunter (2005), Ballabriggs (2011) and Many Clouds (2015)? He has three chances - Lake View Lad, Vintage Clouds and Warriors Tale.

Kelly became the first woman to win a Grade One race in Britain when she guided Tea For Two home in the Kauto Star Novices Chase in 2015

Two women have rides in the race as they look to become the first female jockey to triumph - Lizzie Kelly is on Tea For Two, while Rachael Blackmore rides Valseur Lido.

Might a previous runner take the spoils? The 2017 Scottish-trained winner One For Arthur returns as does Bless The Wings, who was third for Elliott last year in a 1-2-3-4 for horses trained in Ireland.

Will champion Irish trainer Mullins follow up his first Cheltenham Gold Cup win, last month with Al Boum Photo, by claiming the National for a second time after Hedgehunter's triumph 14 years ago?

Ruby Walsh, number one jockey for Mullins, and the Cheltenham Festival's all-time leading rider, will be 40 this year and has picked Rathvinden ahead of 2018 runner-up Pleasant Company and fellow stablemate Livelovelaugh.

Two horses - Don Poli and Outlander - have new owners and trainers after being sold at auction after racing on Thursday. Don Poli was bought for £170,000 by Darren Yates and will carry his racing silks with the initials DY.

Pundit predictions

Gina Harding, BBC reporter

1 Vintage Clouds 2 Up For Review 3 Jury Duty 4 Rathvinden

Lining up for a trainer who won the race in 2013, more importantly Vintage Clouds was the subject of a vivid racing dream I had - and the previous two times that has happened, the horses won. Will I get up the 'mystic treble'?

John Hunt, BBC commentator

1 Go Conquer 2 Anibale Fly 3 Minella Rocco 4 Pleasant Company

The best jumper in the line-up for a trainer who has won the race twice, Go Conquer comes into the National after probably his best run ever last time.

Frank Keogh, BBC Sport website reporter

1 Vintage Clouds 2 Jury Duty 3 Rock The Kasbah 4 Rathvinden

A decent second at Cheltenham last month should put Vintage Clouds in position to go even better than his third-placed finish in last year's Scottish National.

Cornelius Lysaght, BBC horse racing correspondent

1 Lake View Lad 2 Rock The Kasbah 3 Minella Rocco 4 Noble Endeavor

Preference is for Lake View Lad because he has a progressive profile, and, to use another much-loved racing cliche, "could be anything" over this extreme distance.

Gary O'Brien, BBC commentator and Racing TV presenter

1 Pleasant Company 2 Lake View Lad 3 General Principle 4 Tiger Roll

With a nice pull at the weights with last year's winner, Pleasant Company can run well again - it might be another season where he didn't perform at his best until the National.

What about safety?

Extensive improvements were made at the Merseyside racecourse before the Grand National meeting in 2013 after two horses had died in each of the previous two runnings of the marathon race.

The race distance was shortened, steps were taken to ensure softer ground and a more flexible plastic core has since been used at many fences.

There have been no serious equine injuries among the total of more than 200 horses that have competed in the last six runnings of the National.

Two horses died in races at the meeting on Friday - Forest Des Aigles was euthanised after breaking a leg while running on the flat in the Topham Chase, while Crucial Role was put down following a fall in the Mildmay Novices' Chase.

Racecourse officials will hope runners and riders come back safely on Saturday with British racing under pressure from politicians and welfare groups to improve its welfare record.