Telecoms giant BT confirmed it has extended its current deal to broadcast Aviva Premiership Rugby games for another four years, making it the longest in the history of the competition.Games from the top division of English rugby will be shown on BT Sports until the end of the 2020-21 campaign, the group said."BT Sport has been a fantastic partner for English club rugby so we are delighted that we have been able to extend our relationship with them for a further four years," Mark McCafferty, the chief executive of Premiership Rugby."This is the longest TV agreement in the history of Premiership Rugby."The broadcaster said it will have live broadcast rights for up to 80 Premiership live matches per season for four years starting from the 2017-18 season, with extended highlights rights for all 135 Premiership matches per season from the 2015-16 campaign."We are enjoying a golden era for rugby in this country with the Rugby World Cup just around the corner and the game's re-entry in the Olympics in the summer of 2016," said McCafferty."This announcement is another indication of the current strength of English rugby."BT added that its sport channel will establish a partnership with English rugby's competition aimed at developing a community rugby programme."We are absolutely delighted to be extending our partnership with Premiership Rugby," said BT Consumer chief executive John Petter."2015 will be an amazing year for rugby in the UK and the popularity of rugby will continue to grow."BT shares were up 0.24% to 452.90p at 15:32 on Monday.