Blind since birth, and educated at schools for the blind in Sheffield and Shrewsbury, Blunkett's chances in life seemed limited. Following his father's death, he was sent on assessment to the School for the Blind in Worcester (New College Worcester), where he failed to gain entry. His failed assessment is said to be partly deliberate, due to his rebellious nature and dislike of public schools. However, he later attended the Royal National College for the Blind in Hereford. Indeed, he was apparently told at school that one of his few options in life was to become a lathe operator. Nevertheless, he won a place at the University of Sheffield, where he gained a BA honours degree in Political Theory and Institutions; one of his lecturers was Bernard Crick. He entered local politics on graduation. He worked as a clerk typist between 1967 and 1969 and as a lecturer in industrial relations and politics between 1973 and 1981.
Being tough on immigration and asylum was important for Blunkett during his time at the Home Office. In December 2001, he controversially called for immigrants to develop a greater "sense of belonging" to Britain. In April 2002, he proposed new powers which he claimed would curb illegal immigration and unfounded claims for political asylum.
Meanwhile, his department in Sheffield was accepting immigration applications with only cursory security checks. When a whistle-blower made this public, both the whistle blower and one of Blunkett's subordinates lost their posts, but Blunkett survived.
Another controversial area for Blunkett was civil liberties, which he famously described as "airy fairy".. As Education Secretary, he had repeatedly expressed the intention that, were he to become Home Secretary, he would make the then-incumbent Jack Straw, who had been criticised for being hard-line, seem overly liberal.
On 15 January 2003, he was at the centre of controversy again when at a gathering of Asian and Black Home Office Employees in London he made a joke: "Colin Jackson succeeded, despite being Welsh". The comment caused great controversy amongst senior Welsh Nationalists but the Labour Party rallied around Blunkett and the matter was quietly dropped.
In 2003, he announced an extension of the Regulation of Investigatory Powers Act, which critics condemned as a "snoopers' charter". His Criminal Justice Act 2003 reduced legal safeguards such as the right to trial by jury and double jeopardy rules. He also attempted to introduce compulsory national identity cards (initially called "entitlement cards", though this euphemism was later dropped). The aftermath of terrorist attacks in the USA was offered as a justification to pass this controversial legislation, though no compulsion to carry identity cards was planned.
Lord Stevens, the Commissioner of the Metropolitan Police during Blunkett's tenure as Home Secretary, said of him "If you are ever asked to meet with Blunkett, under no circumstances should you go alone...he is a bully and a liar.
He also introduced plans to introduce criminalisation of possession of what the Government has labelled "extreme" adult pornography, in response to a request from Liz Longhurst, a move that has been criticised by anti-censorship and alternative sexuality groups, as the law will criminalise images involving consenting adults.
Blair regarded it proper for Blunkett to remain Home Secretary while pursuing his pregnant former lover in the courts to ascertain paternity of her unborn child as it appeared of no relevance to his ministerial position. However, at the end of November 2004, it was alleged that Blunkett abused his position to assist his ex-lover's Filipina nanny, Leoncia "Luz" Casalme, by speeding up her residence visa application and later using his influence to ensure that she successfully obtained an Austrian tourist visa. An investigation into these allegations was launched, led by Sir Alan Budd. Shortly before Sir Alan was due to report his findings, an email emerged headed "no special favours, .. but a bit quicker". Though there was no evidence Blunkett was responsible for the email or its title, he resigned as Home Secretary on 15 December 2004, saying that questions about his honesty were damaging the government. Sir Alan's final verdict, delivered on 21 December 2004, concluded that "I believe I have been able to establish a chain of events linking Blunkett to the change in the decision on Mrs Casalme's application."
Budd admitted that the investigation was "not a straightforward matter", because few involved in it could recall the details. His report says:
I believe there are two broad possibilities: Mr Blunkett was seeking special help for Mrs Quinn's nanny (or) he was raising the case as an example of the poor performance of the Immigration and Nationality Directorate (IND). I do not have direct evidence that allows me to choose between the two possibilities.
A fax from Blunkett's office to the IND had not been found during the inquiry but Sir Alan found no evidence of an attempt to conceal or destroy evidence. Following the report's publication, he told reporters: "I have been unable to link Mr Blunkett to the sending of faxes to the IND. There must have been such a link but I have been unable to discover what its nature was."
Blunkett resigned as Home Secretary after being told in advance of Budd's findings. He said: "I want to make it clear that I fully accept the findings of Sir Alan's report, where his findings differ from my recollections this is simply due to failure on my part to recall details."
On the day that Sir Alan delivered his report, a Parliamentary standards committee led by Sir Philip Mawer also upheld a complaint against Blunkett for giving Quinn a taxpayer-funded railway ticket (reserved for MPs' spouses) to the value of £179. Blunkett had already admitted that he had broken the rules, saying that he had made an honest mistake, and repaid the sum in question.
Blunkett was not helped by a series of stinging criticisms of his Cabinet colleagues, made by Blunkett to his biographer Stephen Pollard, which became public days before he resigned. His increasingly public paternity battle (see Private life) was also believed by many to be harming his position. However, many believed that he would be able to salvage his political career.
On 31 October 2005 Blunkett was asked to explain why he had not consulted the Advisory Committee on Business Appointments regarding the directorship. Having placed the shares into an independent trust, "Mr Blunkett said he had asked his three grown-up sons from his first marriage to authorise trustees to "dispose of" the shares. They agreed to the request."
Blunkett's political opponents claimed that a conflict of interest was created by him having been director of and holding shares in a company proposing to bid for government contracts to provide paternity tests to the Child Support Agency – part of the Department for Work and Pensions, of which he was Secretary of State.
An investigation by Cabinet secretary Sir Gus O'Donnell – asked for by Prime Minister Tony Blair – found that although Blunkett had not broken the Ministerial Code by becoming a director of the company or buying its shares, he should have consulted the Advisory Committee before doing so.
However, it was revealed on 1 November that Lord Mayhew of Twysden, who chairs the Advisory Committee, had sent three letters to Blunkett reminding him to seek the committee's advice on his involvement with DNA Bioscience, which he ignored. On the same day, Sir Alistair Graham, chairman of the Committee on Standards in Public Life, said Blunkett had breached ministerial rules.
Blunkett declared that he would not be resigning, saying to a newspaper, "I have done nothing wrong." A statement by Downing Street said that the Prime Minister did not believe that Blunkett's mistake should prevent him from carrying out his job.
It also became public that Blunkett had taken two other paid jobs, one with the international Jewish charity World ORT the main focus of which is the development of hi-tech industries in Israel., and the other with Indepen Consulting, again without seeking advice from the Advisory Committee.
On 2 November, Lord Nolan, a former Chairman of the Committee on Standards in Public Life and architect of the code of conduct, was reported as having said in an interview with the Yorkshire Post, "I think he's more or less admitted that he should have followed the rules. But I think it's the fault of the Government that he has been allowed to see if he can get away with it." Lord Nolan was reported to have continued: "Blair should insist on Ministers all round obeying the rules. I think that if anyone breaks the rules they should be disciplined, otherwise there's no point having the rules." Lord Nolan agreed that this meant that Blunkett should have been dismissed or demoted by the Prime Minister.
On the same day, a scheduled appearance before a House of Commons Select Committee was cancelled at the last minute and Blunkett was summoned to a meeting at Number 10. Later that morning, a spokesman for Prime Minister Tony Blair confirmed Blunkett had resigned at the meeting, stating that his position had become untenable. In a statement, Blunkett claimed that the "lies" of those such as Max Clifford would one day be "dealt with".
John Hutton was appointed as David Blunkett's successor that day. Blunkett's children's trustees decided not to sell the shares in DNA Bioscience after all. In December 2005 it was reported that the company faces insolvency, resulting in Blunkett's shares being worth very little.
Despite his resignation from the cabinet in November, Blunkett continued to enjoy rent-free accommodation in Belgravia, London, at tax-payers' expense until he found new accommodation in mid-March 2006. He also rents a cottage on the estate of Chatsworth House. The controversy gained further press coverage later in 2006, when Tory MP Philip Davies asked when Blunkett was due to vacate the residence. Ironically, this was published only the day before the same newspaper broke the story about him vacating the house, which will now stand empty and be maintained by the government at the tax-payer's expense until another cabinet minister requires an official residence.
In 2005 there was more speculation about Blunkett's private life, this time regarding a young woman and for not disclosing free membership to an exclusive London nightclub, Annabel's. The matter with the young woman has been cleared up following a full apology from the newspaper which printed the original story and his membership at the nightclub has been forfeited.
A character based on Blunkett appeared in the Canadian cartoon series Bromwell High, and a club-night called Electric Blunkett, held at the Sheffield Blind Institute, began in the summer of 2005, although its name was swiftly changed to Electric Blanket. Linda Smith once described Blunkett as "Satan's bearded folk singer". He is the topic of the song Blindness by Manchester group The Fall. He appeared on The F Word with Gordon Ramsey cooking a Shepherd's Pie on 3 June 2008.