Sir David is also to leave his post as the Liberal Democrats' foreign affairs spokesman this summer - paving the way for Paddy Ashdown to carry out an even more sweeping reshuffle of the party's top jobs than anticipated.
Mr Ashdown last night paid a warm tribute, saying said that 'internationally, Sir David Steel has become one of Britain's best- known and most widely respected politicians.'
In a cheerful sideswipe at Baroness Thatcher, Mr Ashdown said: 'The role of an ex-party leader is one of the most difficult in politics. In contrast to some, David has been a model, always a valued background adviser, but never a backseat driver.'
Sir David told his Tweeddale, Ettrick and Lauderdale constituency party last night that there was a 'lot to be said for leaving while I am still enjoying parliamentary life, but while I am yet young enough to contemplate doing something equally constructive and challenging'.
Sir David also acknowledged, however, that boundary changes meant 26 per cent of the constituency would now become new territory thanks to the inclusion of solidly Labour Penicuik. He said that it made 'every sense' for a younger man to take on the task of convincing former Labour voters of the 'political realities' in their new home.
Sir David is likely to go down in history as a key force in modernising the Liberal Party and paving the way for an expanded and credible third force in British politics.Reuse content