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 on April 23 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 last year, completing the quadruple of Boston, London, Chicago and New York victories for the fourth year in a row.

The total prize purse for the London Marathon’s T53/54 wheelchair contests has been boosted this year to $112,000 (£90,000/€106,000) from $84,500 (£67,800/€80,000) in 2016, making them the most lucrative in the world.

Thirty-three 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 de Janeiro last September.

"It’s been an incredible year for me which all started with my wins in Boston and London last April," he said.

"The Virgin Money London Marathon is the biggest race in the world and I’d love to win for 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 Marathon 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 is also likely to be in the hunt as he looks for his first London Marathon victory on his 12th appearance.

That is almost as many as Weir, who is still striving for a record seventh win at the event on his 18th consecutive appearance.

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-place finishes on the last three attempts.

It is also set to be the 37-year-old's last race after becoming involved in a dispute with British Athletics, with Weir claiming coach Jenni Banks threw his £3,000 ($3,700/€3,500) carbon fibre chair across a room during a row at the Rio 2016 Paralympics.

He also claims Banks accused him on deliberately performing poorly in the T53/54 4x400 metres relay heats at the same Games and that he will never compete as part of the British team again.

British Athletics have confirmed that there was "a frank exchange of views between an athlete and relay coach" after the race, adding they have met with Weir to receive feedback from his experience in Rio.

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 World Marathon Majors series, losing only the Paralympic race in Rio where she was pipped on the line by China’s Zou Lihong.

Manuela Schär has finished runner-up to McFadden in the last three years in London.

The 2013 world champion lost by just one second 12 months ago and last year’s Berlin Marathon 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 American racers Susannah Scaroni, Shirley Reilly and Chelsea McClammer could also be in contention.

British interest rests with Jade Jones, the 21-year-old 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 will be defending their crowns. 

Formerly the IPC Athletics Marathon World Cup, the 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 on to claim Paralympic gold five months later.

He faces Rio 2016 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 and will face fellow Japanese Tadashi Hirokoshi, the 2015 world bronze medallist.

Another Brazilian, world champion Aniceto Antonio dos Santos, defends the T13 title, and the US’s Paralympic multi-medallist Ray Martin will be seeking 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 will bid to regain the women’s T11/12 title against the respective Rio 2016 silver and bronze medallists, Misato Michishita of Japan and Brazil’s Edneusa de Jesus Santos Dorta.