One of Usain Bolt’s training partners has reignited the debate about athletes switching nationalities by deciding to run for Great Britain. Miguel Francis, a promising 22-year-old sprinter who ran the seventh fastest 200m in the world last year, competed for Antigua and Barbuda at the 2014 Commonwealth Games and the 2015 world championships but has been given permission to run for GB by the governing body of athletics, the IAAF.

The news is bound to cause controversy given the IAAF president, Seb Coe, announced a ban on changes of nationality in February because he felt the system was open to abuse and rules were being manipulated.

Francis, who has a 200m personal best of 19.88sec and is considered an outstanding relay runner, was allowed to switch because he applied before the Rio Olympics.

Francis’s decision will also revive the “plastic Brit debate”, which blew up when five athletes switched allegiance to Great Britain in the buildup to London 2012. They included the 100m hurdler Tiffany Porter, who has since captained the GB team and won a world championship bronze and European gold medals. Another five athletes switched in 2015, including Zharnel Hughes, who also trains with Bolt at the Racers’ club in Jamaica.

The International Association of Athletics Federations has allowed Francis to switch because he was born in Montserrat, which is a British overseas territory. His family was forced to move to Antigua and Barbuda after a volcanic eruption in 1995 when he was a few months old. It is understood British Athletics did not actively seek Francis’s transfer of allegiance and was caught on the hop when told.

Francis’ decision to switch will undoubtedly strengthen Britain’s 4x100m relay squads and intensify competition for places in the 200m.

Last year Adam Gemili finished fourth in the 200m in Rio, missing out on a medal by a thousandth of a second, while Hughes and Nethaneel Mitchell-Blake are also considered future medal hopes by British Athletics’ coaches. Francis, who is 6ft 4in and trained by Bolt’s coach, Glenn Mills, is faster than all of them. He was considered a medal contender for Rio before picking up a hamstring injury and missing the Olympics.

British Athletics said it had received confirmation from the IAAF that Francis was eligible to compete for Britain “with immediate effect”.

“Francis started the process to transfer allegiance from Antigua and Barbuda in August 2016, prior to the Olympic Games in Rio, and is now eligible to compete subject to meeting the required selection criteria for a championships team,” it added.

The debate about athletes switching allegiance is unlikely to go away. In February the IAAF set up a working group to agree new rules by the end of the year, with Lord Coe admitting: “It has become abundantly clear that with regular multiple transfers of allegiance the present rules are no longer fit for purpose. Athletics has to be based on national teams and is particularly vulnerable.

“The rules do not provide protection necessary for individual athletes, they are open to abuse. Many federations regularly receive reports of athletes who are available for trade.”

The former World Anti-Doping Agency chief, David Howman, has been appointed the chairman of the board of the IAAF’s independent Athletics Integrity Unit, which began operating this week. The AIU will oversee athletics’ anti-doping programme as Coe seeks to restore the credibility of a sport damaged by doping and corruption scandals.

Howman, who was the Wada director general for 13 years until 2016, said: “This is going to be a great role. Integrity is not about lists of rules to help athletes compete – it is a key principle that must be ingrained in the way athletes live their lives and compete. The IAAF is addressing this differently to any other international sports federation. It is taking a brave, bold stance by looking at the total package of integrity from the athletes’ point of view.”