Maclennan, Robert Adam Ross (1936-...), a Scottish politician, became the last leader of the United Kingdom's Social Democratic Party (SDP) in 1987. He succeeded David Owen, who resigned after the SDP voted to negotiate merging with the Liberal Party. Maclennan's main task as leader was to discuss the arrangements of the merger. The merger went ahead in 1988, forming a new party called the Liberal Democrats, of which Maclennan became a member.