BY Sir Mo Farah's standards, his London marathon debut April 2014 wasn't exactly his finest two hours. Those who expected him to seamlessly transfer his 5,000m and 10,000m form to the longer distance and break Steve Jones' 29-year British record were surprised to see him finish eighth in 2:08.21, some four minutes behind the winner Wilson Kipsang. But the race could yet prove to be far more damaging than that.

Not only was it revealed yesterday that the US anti-doping agency (Usada) were still investigating the infusion of a controversial supplement given, under the orders of controversial US coach Alberto Salazar, to the Somali-born distance runner in the lead-up to the event, yesterday came the allegation that his handlers at UK Athletics may not have properly recorded it. If it isn't British Cycling and Team Sky, it is Salazar and by extension Farah: not a day seems to go by right now without further developments in the quest to make sport a doping free zone. This is either good or bad news, depending on which way you look at it.

Salazar and the Nike Oregon Project (NOP) have been under investigation by the Usada since 2015, but they now also appear to be in the crosshairs of the FBI. The news, reported by the BBC, that the contagion could stretch as far as UKA was an unwelcome new development in the saga.

The furore surrounds the use of a substance called L-carnitine, a naturally occurring amino acid often prescribed as a supplement for heart and muscle disorders. Although not banned by Wada, infusions of more than 50ml in the space of six hours are prohibited. The infusion in question came in early 2014, shortly before Farah's debut marathon appearance.

While both Salazar and Farah strenuously maintain that they have never broken any rules - a spokesperson for Farah said the infusion was "well below" the limit permitted under the Wada code - the L-carnitine infusion administered to Farah remains under investigation.

While a UKA spokesperson said the organisation fully co-operated with the anti-doping authorities and provided "information" relating to the infusion, including the amounts, the BBC yesterday contradicted that claim and instead said that all data may not have been recorded properly. According to the BBC, the UKA also failed to directly answer repeated requests for detail on whether medical protocols on record-keeping were followed.

The report alleges that staff failed to centrally log key data into the UKA system, leaving investigators unable to establish beyond doubt what the infusion levels were. It all came just one day after Ukad chief executive Nicole Sapstead had spoken at the Tackling Doping in Sport conference on Wednesday to highlight the importance of "accurate and timely record-keeping". "It is vitally important that all sports governing bodies keep their medical records up to date for their athletes," she said. "It protects your organisation and your athletes."

The interim report, leaked by Russian hacking group the Fancy Bears, and picked up by the Sunday Times, cites evidence that many of the L-carnitine infusions carried out by Salazar on some of his athletes were "almost certainly" more than 50ml and therefore doping violations. It includes the following entry relating to Farah, a four-time Olympic gold-medal winner: "Oregon Project athlete Mo Farah received an L-carnitine infusion from British physician Robin Chakraverty in April 2014."

Salazar is said to have sent instructions by email to Barry Fudge, a UK Athletics physiologist, to assist him in "preparing an L-carnitine infusion for Mo Farah to use prior to Farah's marathon debut, set to occur in the London marathon" on 13 April 2014. The Salazar email to Fudge included an infusion protocol used on other, unnamed, NOP athletes, but Usada's scientists believe that large increases in L-carnitine levels in several NOP athletes' bodies after infusion would not be possible if the 50ml limit was adhered to.

In Farah's case, according to the report, Usada had not obtained medical evidence of the dosage taken before the race. "Usada continues to investigate circumstances related to L-carnitine use by Mo Farah," the report said. Farah, who was knighted in the New Year’s Honours List, continues to stand by his coach and frequently insisted that he is a clean athlete.

If allegations of performance-enhancing substances at the Nike Oregon Project weren't bad enough, yesterday there were also suggestions that Farah could also be wearing illegally performance-enhancing Nike shoes in training. The sports manufacturer, which is a pioneering a bid for its star athletes to go inside two hours for the marathon, unveiled new Zoom Vaporfly Elite running shoes earlier this week which contain a carbon fibre plate in the soles, but the IAAF admitted on Wednesday that were under investigation after claims that they contain illegal springs.

'We are aware of the speculation around the shoe and have received inquiries about new designs of shoes currently being worn by elite athletes," and IAAP spokesman said.

“As I’ve said many times, I’m happy to be tested any time, anywhere and have any of my samples tested or retested now or at any time in the future, by any official body,” said Farah recently.