This is the BBC.

As I watched Theresa May and Amber rubbed the home secretary on the ropes this week,

I was taken back to a moment that I was asleep on a bed in a hotel just down the road, here in Westminster.

I've been up all night covering the local elections in 2006.

I later worked out that I've been asleep for precisely 11 minutes when the phone went to say the home secretary's quit.

He wants to drive home, he'll do one interview with you only, and he'll only do it if you're at the home office in 10 minutes.

Charles Clark had resigned.

The connection between that scandal then and this scandal, immigration policy, set by politicians, set by ministers,

but implemented by officials in a way that caused a crisis.

It is with deep regret that I'm today leaving the office of home secretary, in which it's been my great honour to serve for the past 16 months.

In this role, as in pretty good...

Charles Clark's successor as home secretary back then was Labour's John Reed, who invited me into the home office to film with him after just a few days in the job.

He wanted to prove that he'd got a grip, but off camera, he told me an extraordinary story,

a story that had made the very few hairs on his head stand up and mine too.

He'd made a surprise visit to the immigration office in Croyton.

He'd gone up to one woman sat behind a desk and he'd asked her what her job was.

When she explained that she was dealing with some incredibly sensitive area of immigration policy,

she boasted that she created a new filing system and she pointed to it.

It was a cardboard box.

She continued that when she'd arrived in the job, she'd found not just dozens but hundreds of files,

trapped behind filing cabinets and radiators, when nobody had found them.

Reed, seeing his career flash before his eyes, said in how long have you been in this job?

...