2018 Gold Cup winner Native River and jockey Richard Johnson are back at Cheltenham this year to defend their crown

Cheltenham Festival Venue: Cheltenham Racecourse Dates: 12-15 March First race: 13:30 GMT Coverage: Live commentary on BBC Radio 5 Live and BBC Radio 5 live sports extra, plus text commentary, racecards and reports on the BBC Sport website and app.

With the 2019 Cheltenham Festival starting on Tuesday 12 March, here are some of the stories and issues that are likely to headline at jump racing's showpiece event.

Altior: the star

Nicky Henderson-trained Altior is undefeated in five hurdle races and 12 steeplechases

History beckons for the reigning Queen Mother Champion Chaser Altior if, as is widely anticipated, he successfully defends his crown and extends a three-year-plus winning streak to a record-equalling 18 races on the trot.

The brilliant nine-year-old, trained for owner Patricia Pugh by Nicky Henderson and the mount of jockey Nico de Boinville, is undefeated in five hurdle-races and 12 steeplechases, a patch of the deepest hue of purple going back to October 2015.

Three of those successes have been at successive Festivals: first, the Supreme Novices Hurdle of 2016, followed by the Arkle Trophy and Champion Chase.

The current holder of the jumping record is the four-time long-distance hurdling champion Big Buck's, trained by Paul Nicholls for the financier Andy Stewart and family, whose colours weren't lowered during the 48 months from January 2009.

Henderson, guide of the charismatic chasing star Sprinter Sacre from virtual oblivion to a second Champion Chase win in 2016, admits to sleepless nights because of the high level of expectations surrounding Altior.

Without meaning to rain on any parades, it should just be said that the horse's trademark spectacular jumping was not always as slick as usual last time he raced, at Ascot in January.

Anyway, back to expectations: with 60 Festival wins over the years, they're high for the entire Henderson team whose challenge is spearheaded by hat-rick-seeking Buveur D'Air in the Champion Hurdle and heavily-backed youngster Angel's Breath against Al Dancer in the Supreme Novices Hurdle.

Welfare changes: nerves will be jangling

There's no doubting that these are nervous times for officials at Cheltenham - also for racing's regulator, the British Horseracing Authority, and for national hunt racing as a whole.

The pendulum of welfare concerns, which once annually pointed unerringly hard at the Grand National, has swung dramatically in the direction of jump racing's headquarters and its big four days of the year.

Just as changes to the famous course at Aintree seem to have been remarkably successful, the statistics surrounding in particular equine fatalities at recent Festivals make more alarming reading.

A list of measures has been introduced by the Authority and it's important they prove effective.

Because while the risks are acknowledged but - with effective safety measures in place - considered acceptable by insiders and fans (of which there are many: over 260,000 on course during the 2018 Festival and millions more following on radio, TV, online and in high street betting outlets), others further afield remain less convinced.

Meanwhile, it will be interesting to see what comes of the Authority's warning that it is monitoring jockeys' use of whips and that penalties may increase in future if too many are deemed guilty of a 'win at all costs' mentality, thereby prompting the conclusion current punishments are insufficient.

Elliott and Tiger on a roll

Jockey Davy Russell rode Tiger Roll to victory at last year's Grand National

When Gordon Elliott, once a relatively low-profile jump jockey, started training in the 2005-06 season, one of his first successes was in the following year's Aintree Grand National with Silver Birch.

Quite an entrance. And since Silver Birch he's steadily climbed towards the top of the racing tree, more recently with steadfast support from aviation mogul Michael O'Leary's Gigginstown House Stud racing arm, with which he tasted more Aintree glory in 2018, this time with Tiger Roll.

At Cheltenham, County Meath-based Elliott wrestled the Festival's leading trainer title away from Irish arch-rival Willie Mullins (who'd won the previous four) in 2017 and followed up a season later when Ireland netted 17 wins out of 28 races.

And he's favourite to make it three in a row with a powerful squad headed by big Champion Hurdle fancy Apple's Jade and Tiger Roll himself looking for a fourth Festival success.

Having taken the 2014 Triumph Hurdle and the National Hunt Chase of 2017, Tiger Roll defends the Cross Country Chase trophy won on the way to Aintree - and judged by a recent effort at Navan he may take some pegging back.

Talking of the top trainer and leading jockey…

Gordon Elliott, Willie Mullins, Nicky Henderson and Paul Nicholls is the pecking order among the trainers if the betting is to be believed, but there's a chance that the odds being offered for Paul Nicholls (16-1 from some bookies) are the most interesting.

The 10-time champion trainer, who's been enjoying a rewarding season with leading chasers like King George VI Chase winner Clan Des Obeaux - partly-owned by Sir Alex Ferguson - and Cyrname, has fancied runners left, right and centre, including 'Clan' in the Gold Cup.

Most of them will be ridden by 20-year-old Harry Cobden, who's way down the list of odds on offer for the week's most successful rider at about 20-1. With the form of the Nicholls team, that's sure to tempt some.

At the head of the market are standing dishes Barry Geraghty and Ruby Walsh, who was injured during the 2018 Festival. Meanwhile Geraghty's employer, the businessman JP McManus, is favourite to be leading owner with Gigginstown second-best in the betting.

Cheltenham: in touch with its feminine side

So, we're one year on from female jockeys recording a record Festival tally of four victories when first Lizzie Kelly (Coo Star Sivola, Festival Plate), then Katie Walsh (Relegate, Champion Bumper), then Bridget Andrews (Mohaayed, County Hurdle) and finally, despite dislocating her right shoulder during the race, Harriet Tucker (Pacha Du Polder, Foxhunters Chase) were all successful.

Though Walsh has now retired from the only frontline sport where women athletes compete daily against men on identical terms, Kelly, Andrews and Tucker all return intent on more glory.

And they're joined by Rachael Blackmore, who lies second in the Irish jump jockeys table, and the irrepressible Bryony Frost.

But it's not just jockeys: trainer Emma Lavelle saddles in-form Paisley Park as favourite for the Stayers' Hurdle in which the Jessie Harrington-trained Supasundae will be a formidable opponent; Kayley Woollacott's Lalor is a leading hope for the Arkle Trophy; Aso (Ryanair Chase) leads Venetia Williams' never to be ignored Festival challenge; and a few shrewdies like the look of the Sue Smith-trained Vintage Clouds against Coo Star Sivola in the Festival Plate. And there will be more.

With Irish-trained mares Apple's Jade and Laurina major contenders for the Champion Hurdle - and detailed research into the attendances at racing fixtures finding that 39% are female, compared to the British sports average of 20% - perhaps racing is more in touch with its feminine side than it realises.

The mystery of Presenting Percy

Presenting Percy is one of the favourites to win the 2019 Cheltenham Gold Cup

Actually, to be fair, when talking about leading Cheltenham Gold Cup fancy Presenting Percy, there isn't so much mystery about the horse - owned by Philip Reynolds, son of the former Irish prime minister Albert Reynolds.

Victories in two Festival races, the 2017 Pertemps Handicap Hurdle and the RSA Chase of 2018, have made sure of that.

It's his trainer Pat Kelly who's rather more cryptic.

Not only does he go about his business with an almost Trappist-like silence, making little contact and declining all interviews, but it's said that only a few know the exact location in County Galway of his tiny operation - and the eight-year-old Presenting Percy's jockey Davy Russell is not one of them.

Various theories abound for the reticence of Kelly, who also won the Pertemps Hurdle in 2016 with Mall Dini, but as he doesn't talk it's hard to come up with a definitive answer.

What is clear, however, is that he has a good relationship with the racecourse at Galway City, which is a right-handed track because officials there switched around their fences to emulate left-handed Cheltenham so that Presenting Percy, who's only run once this season and that was a win over hurdles, could get some match practice.

Plenty of the thousands of visitors from Ireland - they account for 30% of ticket sales - are shouting the odds about Presenting Percy's prospects. Not, however, his trainer.

It's a wide-open Gold Cup…

Presenting Percy and the already mentioned Clan Des Obeaux are just two of a dozen or more leading fancies for the Gold Cup, a race won in 2018 by Native River, trained by Colin Tizzard and ridden by champion jockey Richard Johnson in the colours of owners Garth and Anne Broom (Brocade Racing).

Native River returns to defend his crown - along with Johnson who had stitches in a face wound after a fall at Taunton but expects to be fit for day one the Festival.

With some more than decent subsequent form in the boo, Native River is joined by fellow Tizzard hopefuls Thistlecrack and Elegant Escape.

Famously, or he might say infamously, top Irish trainer Willie Mullins has saddled horses to fill the Gold Cup runners-up spot on six occasions without ever winning, but his horses Kemboy, Bellshill and Al Boum Photo all have their fans.

That's eight mentioned before we get to the horse Native River defeated in 2018, Might Bite - or Bristol De Mai, Haydock's Betfair Chase winner, when Native River, Thistlecrack, Clan Des Obeaux and Might Bite were all behind. New sponsor Magners has a good one with which to start off.

My tips for the 'Big Four' races:

Champion Hurdle: the seven pounds less weight to be carried by mares, including the outstanding Apple's Jade, may be decisive, and I'm going for her.

Queen Mother Champion Chase: it has to be history for Altior.

Stayers' Hurdle: Paisley Park has carried all before him and is expected to continue to do so. I'm also expecting a good show from outsider Sam Spinner.

Gold Cup: Native River has very solid form in defeat of late, and it may be hard to stop a repeat of his 2018 success.

Cornelius Lysaght, racing correspondent, will be part of the Cheltenham Festival coverage on BBC radio and the BBC Sport website.