Endurance coach Terrence Mahon says GB's marathon runners need to prove themselves at shorter distances first.
Italian race walker Alex Schwazer has been banned for three and a half years by the country's National Olympic Committee (CONI) for doping.
Susan Partridge and Sonia Samuels have been named on the Great Britain team for the marathon at the World Championships in Moscow in August.
The Government has been accused of a "shabby and shambolic" appointment process after Nick Bitel was named the new chairman of Sport England.
Mo Farah wants to mark his marathon debut in London next year by adding to his growing collection of British long-distance records.
Ethiopia's Tsegaye Kebede claimed a hard-earned victory in the 2013 London Marathon, while Priscah Jeptoo of Kenya won the women's race.
Mo Farah claims he learned the biggest lesson of his life after sticking to his controversial plan to run to halfway in the London Marathon.
Mo Farah will finally take to the start line at the Virgin London Marathon on Sunday still bursting with enthusiasm for the race.
David Weir returns to the title trail at the Virgin London Marathon with his hunger for success undiminished.
Justin Gatlin will compete against six-time Olympic gold medallist Usain Bolt at this summer's Golden Gala event in Rome.
Tatyana McFadden has promised to race with the victims of the Boston bombings in her heart when she bids for another victory in London.
The number of police officers on duty for the London Marathon has been boosted by 40 per cent to provide reassurance.