The judge's departure leaves the IICSA in disarray, for she is the third chair in just two years - though the inquiry has not yet heard a single piece of evidence, and is not set to do so until next year. Dame Lowell's pay and expenses package was worth more than £500,000 a year. This newspaper has learned that Ben Emmerson QC, counsel to the inquiry, who some have suggested could end up as her successor, is paid £1,700 a day, and in the past financial year earned £408,000 - more than Dame Lowell's £360,000 basic salary.
There was widespread disbelief at Dame Lowell's resignation letter, which gave no reason for her departure. Keith Vaz, chairman of the Commons Home Affairs Select Committee, has said he will insist on her giving evidence to explain her actions to MPs. She followed up her letter with a public statement, in which she spoke of IICSA's 'legacy of failure, which has been very hard to shake off' - apparently a reference to the departure of the two previous chairs. The Home Office spokeswoman said the Government rejected the notion that IICSA was a failure, saying: 'They were her words, not ours.'
This newspaper was instrumental in causing the departure of the second IICSA chair, former Lord Mayor of London Fiona Woolf, after we revealed she was socially close to the family of former Home Secretary Leon Brittan - then subject of allegations, later dismissed, of sexual abuse.
Legal sources say there was widespread dismay among IICSA's staff and advisers that Dame Lowell seemed unable to get to grips with the colossal amount of material the inquiry was generating, which left her 'overwhelmed and drowning', while handicapped by her 'blurry' knowledge of English law.
At the preliminary Janner hearing, she seemed to struggle with the very law under which IICSA was established, the Inquiries Act 2005, and unsure whether she could issue orders restricting media reporting. It was also noted that she appeared unfamiliar with the role of a judge during a hearing, failing to invite opposing arguments in the normal way.
'There were a lot of bewildered barristers in court that day,' one source said.
She added: 'This has been building up for months. It wasn't what Dame Lowell wanted, but what the world saw in court has been evident behind the scenes for a long time. In the end, her resignation became inevitable.'