It was during Wolfe's period as leader that the party had considerable electoral success in elections to the Westminster parliament, winning 30% of the vote in Scotland and 11 of the 71 Scottish seats in the October 1974 General Election, though Wolfe failed to win a seat of his own in West Lothian in the two general elections of that year, despite gaining an increased share of the vote. His exclusion from the powerful new group of SNP MPs caused some difficulties for his leadership of the party. However, following a difficult period which saw the passing of the Scotland Act 1978, a number of internal divisions in the SNP and the failure of the party to win in a series of by-elections, in 1978 Wolfe announced his intention to stand down as leader after almost ten tumultuous years in office. The resultant loss of influence led to his being sidelined as the SNP moved into the 1979 general election campaign, and a disastrous performance in which the SNP only managed to retain 2 of their 11 MPs. Wolfe was succeeded by Gordon Wilson at the SNP Annual National Conference in September 1979.