A group 20 competitors - which includes Sir Mo Farah and Katarina Johnson-Thompson and is being led by Adam Gemili - announced last month they had challenged the existing guidelines.

This followed the International Olympic Committee (IOC) enabling countries to be more flexible with their use of its Rule 40.

A landmark ruling in Germany earlier this year significantly scaled back the power of the longstanding regulation.

Countries including the United States and Australia are among those to have relaxed Rule 40 guidelines, which subject athletes to sponsorship restrictions before and during the Games.

The BOA has followed suit, but only allowed athletes to issue a generic thank you message during the Games period "provided it doesn't contain any Olympic branding, such as a medal or Team GB kit or references".

The BOA has insisted it is an "entirely independently funded organisation, which is not in receipt of public funding", unlike some of the other countries who have changed their guidelines.

While confirming it has responded to the legal challenge, the BOA has expressed concern over whether it is negotiating with athletes, agents or commercial organisations.

The organisation claimed "ongoing legal tactics" were being conducted in the background.

"The BOA can confirm it has formally responded to the recent legal challenge brought against the BOA interpretation of the IOC Rule 40 in the UK," a BOA spokesperson said.

"Since we learned of the legal challenge - through the media - we have proactively sought to understand the athletes' concerns and who, in fact, we are negotiating with - athletes, agents or commercial organisations.

"Last week, we had a positive meeting with representatives of the athletes who have challenged Rule 40 and we continue to impress upon all concerned that we are open to dialogue and reaching a positive outcome that balances the desire for individual athletes to maximise their personal sponsorship revenues with the need to preserve and enhance a system that has collectively sold rights for the benefit of the whole of Team GB, including smaller sports and less high-profile athletes.

"However, despite those encouraging conversations, we have been dismayed by the ongoing legal tactics being conducted in the background, which in no way reflects the spirit of the discussions held.

"Therefore we have been forced to respond fully and robustly to the legal challenge and have done so in the best interests of all of the athletes we serve and the BOA - a not-for-profit independent organisation that receives no taxpayer or Government funds.

"All monies raised by the BOA are prioritised towards providing athletes with the best support in the performance environment.

"In the four-year period to Tokyo 2020 we will have taken over 700 athletes to nine multisport events, including youth Olympic Games and both senior winter and summer Games.

"We reiterate that it is clearly not in the interest of any party to enter into a protracted legal dispute ahead of the Tokyo 2020 Olympic Games.

"As such, we continue to act in good faith and make ourselves available for further discussions with a strong desire to find a positive solution for the benefit of all athletes through constructive, open and transparent dialogue."

Gemili claimed last month that the group of athletes launched the challenge after the change from the BOA did not go far enough.

Rule 40 was amended following a change to the Olympic Charter, forced upon the IOC following the decision in Germany.

It previously warned that "no competitor, team official or other team personnel who participates in the Olympic Games may allow his person, name, picture or sports performances to be used for advertising purposes during the Olympic Games".

This was seen as a major reason why companies have been willing to sign up as part of the lucrative The Olympic Partner (TOP) sponsorship scheme which guarantees huge exposure during Games-time.

Athletes have complained, however, that it prevents them from making money during the most important time of their career, particularly with sponsors who are not part of the TOP programme.

The rule now reads: "Competitors, team officials and other team personnel who participate in the Olympic Games may allow their person, name, picture or sports performances to be used for advertising purposes during the Olympic Games in accordance with the principles determined by the IOC Executive Board."

IOC President Thomas Bach claimed earlier this year that there was no "one size fits all" solution, with implementation remaining down to the respective NOCs.

Bach said this would be due to how NOCs were funded in different countries.