He was the party's Chief Executive between 2003 and 2009. During his employment by the Liberal Democrats at a national level, he was credited with winning 13 parliamentary by-elections for the party (11 gains and 2 holds), out of a total of 74 by-elections held—a success rate of 17.5%. The Eastbourne by-election in 1990 was claimed by Rennard as rescuing the Liberal Democrats from their very weak position following the merger of the Liberal Party and the SDP, and saw a 16,923 Conservative majority become a Liberal Democrat majority of 4,550. The by-election followed a major row between Rennard and Paddy Ashdown over the party leader's initial opposition to the Liberal Democrats fighting the by-election. A by-election in Christchurch during July 1993 saw the Liberal Democrats gain the seat from the Conservatives by the largest swing (35%) against any British government since 1918.