The world’s richest wheelchair marathon returns to the streets of London on Sunday 23 April when two of the greatest wheelchair racers ever seen defend their Virgin Money London Marathon titles against the largest elite fields in the history of the event.

Switzerland’s ‘Silver Bullet’ Marcel Hug and USA’s ‘Queen of the Roads’ Tatyana McFadden will be outstanding favourites to claim the US$20,000 winners’ awards in London.

Hug has dominated the men’s contest in the inaugural Abbott World Marathon Majors Wheelchair Series over the last 12 months. He will be seeking his third London Marathon victory after edging out Australia’s course record-holder Kurt Fearnley and Britain’s six-time winner David Weir last April.

McFadden is aiming for a record fifth straight women’s crown, a feat never achieved before in any London Marathon elite race – men’s, women’s or wheelchair. She won all but one of the five World Marathon Majors races she entered in Series X, completing the quadruple of Boston, London, Chicago and New York victories for the fourth year in a row.

The total prize purse has been boosted this year to US$112,000 from $84,500 in 2016, making the London Marathon’s T53/54 wheelchair contests the most lucrative in the world. No fewer than 33 men and 14 women will pursue the record awards on offer to the top 10 finishers in each event – more racers than ever before in 35 years of London Marathon wheelchair racing.

Hug’s victory last year came just six days after winning the Boston Marathon and the 31-year-old has been unbeatable over 26.2 miles ever since, winning six out of six World Marathon Majors races including the Paralympic Games gold medal in Rio last September.

Hug said: “It’s been an incredible year for me which all started with my wins in Boston and London last April. The Virgin Money London Marathon is the biggest race in the world and I’d love to win a third time. It’s never easy though. Anything can happen in wheelchair racing and the field this year is stronger than ever.”

Hug’s closest rival in recent races has been Fearnley, the 2009 and 2013 London winner, and the two-time Paralympic champion is likely to be the Swiss man’s main challenger again.

South Africa’s 10-time Boston Marathon winner Ernst van Dyk will also be in the hunt. He is looking for his first London Marathon victory on his 12th appearance here.

That’s almost as many as Weir, Britain’s hero of the London 2012 Paralympics who is still striving for a record seventh win at the event that’s closest to his heart. Weir won his first London Marathon in 2002 and his sixth 10 years later, but he has had to settle for second, second and third on the last three attempts.

This will be his 18th consecutive appearance and the ‘Weirwolf’ admits it is a race he would love to win one more time.

“This is the race I love; it’s been in my blood since I was eight years old when I first saw it on TV,” said Weir who won the Mini London Marathon seven times as a junior.

“The London Marathon has always been part of me and I will always be up for it. It was the first race I ever wanted to win and to have won six is amazing. I’m not even thinking about a seventh, though. If it happens, it happens. If I won a seventh maybe that would be a reason to call it a day, but I’ve got beat Marcel first.”

Others likely to be in the hunt for medals include Josh Cassidy, Canada’s 2010 winner and holder of the world’s fastest time; 2015 victor Joshua George of USA, the reigning world champion; and veteran Swiss Heinz Frei, the official world record holder who has won here three times in the past.

Up-and-coming American Aaron Pike could also be one to watch.

All eyes will be on McFadden in the women’s race after the American’s fourth London victory in a row last year. She has won four of the five marathons she's entered in the current Series, losing only the Paralympic race in Rio where she was pipped on the line by China’s Zou Lihong, the width of a tyre separating the pair after 26.2 miles.

Manuela Schär has been McFadden’s runner-up in the last three years here. The 2013 world champion lost by just one second 12 months ago and last year’s Berlin Marahton champion is likely to be McFadden’s main threat again.

Two-time winner Amanda McGrory is looking to get back among the medals after finishing fourth in 2016, while fellow US racers Susannah Scaroni, Shirley Reilly and Chelsea McClammer could also be in contention.

British interest rests with Jade Jones, the 21-year-old Teessider who is coached by Dame Tanni Grey-Thompson.

Hug and McFadden are just two of six reigning World Para Athletics Marathon World Cup champions who’ll be defending their crowns on 23 April.

Formerly the IPC Athletics Marathon World Cup, this annual contest of seven races for elite para-athletes is being staged as part of the London Marathon for the fourth time.

The other returning champions include China’s Li Chaoyan who won the T45/46 contest for arm amputees last year before going to claim Paralympic gold five months later. He faces Rio bronze medallist Manuel Mendes of Portugal, 2013 world champion Alessandro di Lello of Italy and Brazil’s 2015 world silver medallist Alex Pires da Silva.

Yutaka Kumagai defends his T11/12 title in the race for visually impaired athletes. He’ll face fellow Japanese Tadashi Hirokoshi, the 2015 world bronze medallist.

Another Brazilian, world champion Aniceto Antonio dos Santos, defends the T13 title, and USA’s Paralympic multi-medallist Ray Martin seeks a third straight victory in the T51/52 wheelchair race against Spain’s Santiago Sanz.

Spain’s two-time winner and former world record holder Maria Paredes Rodriguez bids to regain the women’s T11/12 title against Rio silver and bronze medallists, Misato Michishita of Japan and Brazil’s Edenusa de Jesus Santos Dorta.

The full entry lists for all wheelchair and World Para Athletics Marathon World Cup races are available here.