Nick Timothy makes an eyebrow-raising claim in his Telegraph column today: that Theresa May opposed the notorious “Go Home” vans that trundled through diverse parts of the country advising illegal immigrants to leave the country – actually claiming she went as far as to block them – but the scheme was “revived and approved” in a press plan while she was on holiday.

Some people are assuming that this story is flatly untrue, and not without good reason. The Times’ Henry Zeffman has dug out a written answer from Amber Rudd saying that while Mark Harper, a junior Home Office minister, approved the vans, he informed May of the scheme ahead of time. The timeframe also stretches credulity somewhat. This is the same government department that having decided to destroy the landing cards of Windrush Britons in June 2009, still had yet to locate a shredder by October 2010. Whitehall takes years to approve advertising campaigns and even the process of hiring a van is not simple: so it stretches credulity a tad to imagine that the Home Office would sign off a poster, hire a van and a driver, all without it either coming across the desk of the Home Secretary or her special advisor. That no official faced dismissal as a result stretches it further still.

However, it is worth noting that Mark Harper, the minister who approved the vans, was the only serving minister to have worked with May at the Home Office who did not continue on in government when she became Prime Minister – instead, she sacked him from his post. The Home Office acting off its own bat would support the belief, not uncommon among civil servants at other Whitehall departments, that Britain’s interior ministry is out of control: that it regularly goes further than its ministerial mandate and that it has an institutional dislike of the people it deals with day to day. So while it seems unlikely that the vans reached the streets without May or her advisors knowing, it is not impossible.

However, that raises more questions than it answers. If you take the Timothy version of events as true, that means that May knew the following things about the Home Office: that they were willing to not only hide the facts from ministers but to actively push ahead with policy proposals that the Secretary of State had dropped. Despite knowing that, she championed a vast increase in the powers and scope of the Home Office in the 2014 Immigration Act and at the peak of her powers in 2016 did the same as Prime Minister. She made no effort to address this troubling culture for the remaining three years she served as Home Secretary, and promoted three of her juniors, none of whom appear to have done anything to address it either, to big jobs across the government. It means that she had little grip over her department an no inclination to assert it. (Indeed, this is why the Secretary of State is held responsible even for decisions that they don’t sign off – as otherwise you have no democratic accountability at all.)

If those vans were sprung on May and her political team, that is even more troubling than the idea that they approved them.