Charles Kennedy has led tributes to Lib Dem politician Conrad Russell who has died after a long illness aged 67.
Conrad Russell was a respected historian and parliamentarian
Mr Kennedy said Earl Russell, son of philosopher Bertrand Russell, was a "personal, political and intellectual rock of support for me".
The Lib Dem peer was also an academic who taught history at Yale, and both University and Kings Colleges London.
He was also a widely published author of political and parliamentary histories. He is survived by two sons.
Earl Russell's great-grandfather was the Liberal Prime Minister Lord John Russell.
Fellow Lib Dem peer Baroness Williams said: "Conrad Russell was a liberal in every fibre of his being, from his wonderful mind to his sometimes agonised body.
"He was a distinctive and distinguished member of the House of Lords, a man of immense learning, elegant oratory and a gentle but perspicacious wit."