Barcelona insist they are remaining "loyal" to their history after signing up to the controversial European Super League but believe the move is part of "great changes" required in world football.

Six English clubs, three Italian sides and Barca along with two other Spanish teams have joined forces to create a tournament that has long been speculated about, despite significant opposition from UEFA and the respective leagues.

Reigning European champions Bayern Munich and last season's Champions League finalists Paris Saint-Germain are not included, though it is said the competition plans to expand to 15 teams before its inaugural season, which will start "as soon as practicable".

The Premier League's so-called 'big six' – Manchester United, Manchester City, Liverpool, Chelsea, Arsenal and Tottenham – are the teams to have signed up alongside Real Madrid, Barca, Atletico Madrid, Juventus, Milan and their city rivals Inter.

Following speculation earlier in the day that prompted a withering response from UEFA, a joint announcement was made by several of the clubs late on Sunday, confirming plans were in place and the initial 12 founding clubs had an agreement.

The lengthy statement revealed the competition will have five guest teams added to the finalised 15 founding clubs and will run as a midweek tournament alongside the domestic leagues – those clubs in power will share €3.5billion "solely to support their infrastructure investment plans and to offset the impact of the COVID pandemic".

While the plans have been met with widespread condemnation due to the competition guaranteeing places – and vast revenue – to a closed group of clubs, those involved claim they have the best interests of football in mind.

Barca are no different, adamant it is their responsibility to help develop the sport.

At their end of their version of the uniform statement, which they did not release until Monday morning, Barcelona said: "FC Barcelona, loyal to its history and its leadership role within the framework of European Football, once again places itself as a leading club with regards to the great changes that are needed in the world of football, thinking always in the how to benefit the club best from a sporting, institutional and financial point of view."

UEFA, the national associations of England, Spain and Italy, plus LaLiga, Serie A and the Premier League signed a joint statement on Sunday that threatened any team involved in the Super League will be excluded from domestic and international competitions.