Scottish duo Callum and Derek Hawkins face a tough battle to qualify for the Olympic Games after it was confirmed the London Marathon field will include all of their main domestic rivals.

With the race on 24 April serving as the selection trial for Rio 2016, the Kilbarchan brothers will be up against top-ranked Scott Overall as well as experienced contenders Chris Thompson and Lee Merrien.

With the qualifying standard at 2 hours and 14 minutes, Callum Hawkins – who ran 2:12:17 in his debut at the distance in Frank in October - will automatically earn a spot in Brazil if he ends up as one of the top two British finishers.

While Derek, who turned down a place at the 2013 world championships, will have to beat his personal best of 2:14:04 to be in contention.

“I expect there’ll be quite a few guys who will get under 2:14 so selection’s up in the air,” said Callum. “But I’m feeling pretty confident.”

2015 winner Eliud Kipchoge will face off against 2014 champion Wilson Kipsang in London with the pair heading an elite field that also includes world record holder Dennis Kimetto and fellow Kenyan Stanley Biwott plus Ethiopia’s triple Olympic gold medallist Kenenisa Bekele,

“This year I will come back to London to compete again with the world's best athletes,” Kipchoge said. “I will work hard to defend my title in London and, together with Wilson, Dennis, Stanley and those from other countries, make it a fast and wonderful race.”

Eritrea’s Ghirmay Ghebreslassie, who took a surprise victory at last year’s world championships in Beijing, will make his London bow.

Meanwhile, Jean Gracia has been named interim chief executive officer/general secretary of the IAAF.

The 60-year old Frenchman will hold the post until a permanent appointment is made later this year.

IAAF president Lord Coe said: "Jean Gracia, who is a former general secretary of the French Federation and a current vice president of European Athletics, brings vast experience and will assist the continued smooth running of the association in the interim."