Where to watch live
Live coverage of every session from all nine days of the World Athletics Championships in Beijing from 22-30 August will be available on BBC1, BBC2 and BBC Radio 5 Live. Highlights will be available after every day of competition on BBC2. Coverage of the morning sessions in China start between 12am and 3am BST, while evening sessions begin between 11am and noon.
Rarely has a World Athletics Championships started under a more threatening cloud and in greater flux than in Beijing, where distractions away from the track will likely dominate the agenda. Droves of unanswered allegations regarding the blood data of a host of athletes hang over the sport and means the meet starts with questions again over its integrity.
Lord Sebastian Coe has been appointed the new president of the IAAF, but with his tenure not starting until after the championships, the British Olympian has a watching brief. Reforms over testing procedures will have to wait and it sees the event undermined by such concerns.
Even the most intriguing narratives of the championships are dominated by doping concerns. Usain Bolt and Justin Gatlin's rivalry has been dominated by questions over the legitimacy of the American's performances, having run the fastest 100m and 200m times in 2015, after previously serving two doping bans.
Meanwhile, Mo Farah makes his first first major appearance since being connected to the stinging allegations facing coach Alberto Salazar, as the Britain attempts to retain his 5,000m and 10,000m titles. The middle-distance headlines are expected to be dominated by Genzebe Dibaba, who looks to become the first women to do the 1500m and 5,000m double.
British athletes to watch
Rutherford, who has attacked the absence of the Union Jack on the GB team kit, heads to Beijing in search of history. Only four Britons – Daley Thompson, Linford Christie, Sally Gunnell and Jonathan Edwards – before him have won a clean sweep of Olympic, World, Commonwealth and European titles and the Milton Keynes-born athlete can join that illustrious list. His main competition comes from world leader Jeff Henderson, fellow American Marquis Dendy and South African pair Zarck Visser and Rushwai Samaai.
The darling of London 2012 takes her place in his first major championships since getting married and giving birth to son Reggie. Ennis-Hill has been hampered by an Achilles problem in her build up to Beijing, delaying the confirmation of her appearance in China until the day of the selection of the British team. The Sheffield-born Olympic champion is pitted against fellow-Briton Katarina Johnson-Thompson in a run-out which will act more as preparation for Rio 2016, than an opportunity to claim gold. Canada's Brianne Theisen-Eaton starts as favourite.
Having ruled out taking on the sprint double in Beijing, Ashes-Smith takes on the 200m having become the first Briton to go under 11 seconds in the 100m. The 19-year-old is the ninth fastest over the longest distance in 2015 and will targeting a place in the final before facing the lottery of the scrap for a medal. All-conquering American Allyson Felix is the huge favourite as the only athlete to go under 22 seconds in the 200m.