The English Premiership, currently known as Aviva Premiership Rugby or more commonly the Aviva Premiership because of the league's sponsorship by Aviva, is a professional league competition for rugby union football clubs in the top division of the English rugby union system. There are twelve clubs in the Premiership. The competition has been played since 1987, and has evolved into the current Premiership system employing relegation to and promotion from the RFU Championship, known as National Division One before the 2009–10 season. Clubs competing in the Premiership qualify for Europe's two main club competitions, the European Rugby Champions Cup and the European Rugby Challenge Cup. The current champions are Northampton. The most recently promoted side is London Welsh, who, after defeating Bristol in the 2014 RFU Championship Final won promotion, after being relegated the previous season.