Leo Blair: The guiding force behind his son's political vision

Leo was a self-made man brought up by foster parents in Glasgow, who believed in aspiration

Tony Blair's political ambitions began at the age of 10, on the day his father Leo's were ended by a stroke he suffered at the age of 40.

Leo's illness was blamed on overwork – as a barrister, law lecturer at Durham University and chairman of the Durham Conservative Association who was looking for a vacant seat to fight. Tony Blair witnessed his father's deep frustration as he learnt to speak again over three long years, and became determined to pick up the baton snatched from him so suddenly.

His father transferred his ambitions on to his two sons and daughter. "It imposed a certain discipline. I felt I could not let him down," he said in 1994, the year he became Labour leader.

As he would point out, Mr Blair was not born into the Labour Party, but chose it. His father's Conservative links were sometimes cited by internal critics of his New Labour project, those who never loved the man they dubbed "Tory Blair".

While the former Prime Minister took a different party path, his father's views undoubtedly influenced his brand of Labour politics. A self-made man, his father's approach was summed up by a belief in "aspiration", instilled in him during an upbringing with foster parents in Glasgow.

Tony likened his father's Toryism to that of Norman Tebbit, the Thatcherite who told the jobless to "get on their bikes" in the 1980s and look for work – as his own father had done in a previous recession. Tony Blair's political inheritance from his father undoubtedly paid dividends for Labour. After four successive general election defeats, and almost being pushed into third place by the SDP-Liberal Alliance, Labour was seen as a high-spending, high-tax, anti-aspiration party. To have a chance of regaining power, Mr Blair judged, it had to woo the aspirational classes of Middle England. Leo Blair helped his son to understand that: New Labour cosied up to the rich not for the sake of it, but because it understood that many in the middle aspired to be better off.

The Blairs' thesis remains still valid: David Cameron, in his speech to the Tory conference last month, said his goal was "an aspiration nation".

Although he did not see much of his travelling father as a child, they became much closer later, especially after the death of Mr Blair's mother Hazel from cancer at the age of 52, just after he graduated from Oxford University.

His father was immensely proud of Mr Blair. When he became Prime Minister in 1997, he wrote to his son to congratulate him, signing off the letter "your loving pa". Later the two men would laugh about the pro-forma reply from Downing Street, which was addressed "Dear Mr Pa" and suggested that Leo contact his MP or Citizen's Advice Bureau.