The Opposition wants his head, insisting that he ought to have reported his two-week post with DNA Bioscience to the Advisory Committee, which ministers are supposed to consult about their business dealings for the first two years they spend out of office. Mr Blunkett has conceded that "with hindsight" it might have been wise, but added the proviso that, as the code is voluntary, he cannot be accused of breaking it.
That is technically true, but it is a close call, and the affair confirms suspicions that Mr Blunkett, an increasingly eccentric politician, has lost any proper sense of judgement about how a public figure should behave. The fact is that Mr Blunkett took a job that conflicted with the government post he must have known he was likely to resume shortly. Moreover, although he gave the job up soon enough, he could still make up to a quarter of a million pounds from shares in this company, bought in trust for his sons for just £15,000.
This rather tawdry situation raises questions about the "revolving door" principle under which politicians and civil servants flit seamlessly from public life into private businesses. More specifically, the affair raises searching questions about Mr Blunkett himself. For this is not an isolated incident; if it were, it would be easier to accept his rather weak explanation about how he came to take the directorship in question only a fortnight before rejoining the Cabinet. Instead, it follows a series of somewhat strange events, several of which point to the same character flaws and to a casual disregard for the rule book.
Above all, there was the business that led to his resignation last December, when it was found out that he fast-tracked a work visa for the nanny of his then lover, Kimberly Quinn. There was the discovery that he gave Mrs Quinn a rail pass to which only MPs' spouses are entitled. Then followed his public battle with Mrs Quinn to gain access to his son, and a subsequent relationship with an estate agent he met at Annabel's nightclub in London, who proceeded to sell her story for a reported £50,000 this autumn.
Mr Blunkett is a serious political player, and one can understand why Mr Blair wanted him back. But it is increasingly looking as though this was a mistake.