Premiership Rugby has secured the longest TV deal in the league's history by agreeing to have matches broadcast by BT Sport for the next six years.

The two parties have added four years to the existing deal, which means that up to 80 live matches per Premiership season will be shown from the 2017-18 campaign.

BT Sport now has the rights to show extended highlights of all the 135 Premiership matches each year from the 2015-16 season.

Premiership Rugby chief executive Mark McCafferty said: "In the 18 months we have been on-air with [BT Sport] our live TV audiences have grown by 50% so it is clear that the partnership is going from strength to strength.

"In almost two seasons of coverage broadcasting the Aviva Premiership BT Sport has set new standards for the live broadcast of rugby. Their innovative style has received great acclaim and we look forward to developing the partnership over the next six seasons."

BT Consumer chief executive John Petter added: "We are absolutely delighted to be extending our partnership with Premiership Rugby. 2015 will be an amazing year for rugby in the UK and the popularity of rugby will continue to grow. We're delighted to be a part of this and that our customers can look forward to another six seasons of the Aviva Premiership on BT Sport."

The deal also includes the rights to air the Singha Premiership Rugby 7s Series until the end of the 2020-21 season.