Mo Farah
Farah's missed tests are alleged to have occurred before he won double Olympic gold at London 2012.Getty Images

Mo Farah missed two drug tests on his road to claiming double Olympic gold at London 2012 as British athletics' finest ever long-distance runner remains embroiled in doping allegations.

The Daily Mail have reported that Farah skipped two unscheduled tests, one in early 2010 and another after Farah began working with coach Alberto Salazar in 2011. Salazar is currently under investigation over doping allegations reported by BBC Panorama.

At the time of the missed test, United Kingdom Anti-doping rules stated an athlete would face a ban from the sport should they miss three tests within an 18-month period. Those regulations have since been adjusted to 12 months but the claims still implicate Farah.

Former 400m Olympic and world champion Christine Ohuruogu was banned for a year in 2006 after missing three out-of-competition tests under the World Anti-Doping Agency's "whereabouts" system.

Regarding the second missed test, which was arranged several months into the start of his relationship with Salazar, Farah has protested his innocence to UKAD having been unable to hear testers ring his doorbell at his house.

Video evidence submitted by Farah's lawyers was later rejected by UKAD upon appeal but the three-time world champion was adamant he was blameless.

Since the missed tests, Farah has won three world titles, three European championships and two Olympic golds, and cemented his status as the most dominant distance runner in world athletics.

Farah's integrity has recently been called into question amid the allegations over the operations of Salazar and training partner Galen Rupp, who finished behind Farah in the 10,000m final at London 2012.

Responding to the latest allegations, UKAD said: "UK Anti-Doping does not disclose personal data relating to an individual's test history. UKAD has a dedicated Athlete Support Officer who works with athletes on the National Registered Testing Pool, and with National Governing Bodies of sport, to ensure they manage their Whereabouts reporting responsibilities."