There are definite benefits to working from home. There’s tea and toast on tap. You’re around to take delivery of that important parcel or let a tradesman in. You can hang the washing or put the rabbits out when you have a spare five minutes.

But it can be lonely, and then there are the door knocks you really wish you hadn’t answered.

I had just such an experience on Monday. As I approached the door and saw a man in his late 20s, big sports bag slung on his shoulder, I had a sinking feeling that he wasn’t about to offer me anything I wanted.

Said bloke proceeded to explain that he was on release from a prison in the north-east, having been banged up for affray after a few too many tinnies down his local. (Not the best opening line I’ve heard).

He couldn’t get a job, and showed me a crumpled-up piece of paper bearing the words “Hawker’s licence”, indicating that he was offering either goods or services door-to-door.

I don’t buy unsolicited goods from or give jobs to cold callers on my doorstep – does anyone these days? So I offered what I thought was a polite “thanks but no thanks”.

The guy’s demeanour changed very quickly. He asked me what my problem was. He swore. The look in his eye suggested he didn’t take rejection well.

I closed my door and locked it, walked away and dialled 999. Outside, I could hear him chuntering to himself and knocking on other doors.

The police call handler was sympathetic, promising to send someone out to catch up with him. “Do you want someone to come and see you?” she asked. I told her I was fine - more furious than fragile, and concerned that he was knocking on the doors of vulnerable elderly folk who would be frightened and intimidated.

But in some small way, I wasn’t fine. I live in a quiet cul-de-sac and this bloke had threatened me in my safest place. My daughter would be heading home from school soon; at best, she’d find the doors locked and think I was out, at worst she’d bump into him. I put a sticky note in the window with a cryptic arrow pointing to a side door.

It was also an uncomfortable challenge to my core beliefs. I think I’m pretty open-minded. Call me a snowflake, but I believe in prison as an opportunity to encourage wrongdoers to lead a better, more considerate life. Evidence shows that locking ‘em up for 23 hours a day just churns out angry young men (mostly) determined to go back to what they know, which doesn’t do anyone any favours.

But it turned out this well-meaning philosophy didn’t extend to having an ex-con on my doorstep, especially one convicted of violence who looked like he might take a swing for me.

It wasn’t even the first time. On a previous occasion, the young man asked if I considered myself to be a Christian. I answered truthfully, defiantly: “No.” He looked mighty annoyed, as if he hadn’t considered this possibility in the 21st century.

Bottom line: if something smells fishy, it probably is. A quick web search suggests that the doorstep hawker claiming to be an ex-prisoners is a well-worn scam practised up and down the country. I had no idea - it’s eye-opening stuff.

The “rehab programmes” they are working with don’t exist, and the goods they are peddling are low-quality and overpriced. They are usually linked to organised crime groups, sharing information and casing the joint for burglary. They become abusive if you say no; say yes, and they (and their mates) will keep coming back, and the prices will rise.

I was amazed to discover there is such a thing as a ‘pedlar's certificate’. It sounds like something out of the 19th century, rag-and-bone man and knife sharpener used to travel round regularly, often ringing a bell to let people know they were there.

You apply to the local police station for it, and you can be fined £200 for working without one - and sentenced for up to six months for carrying a forgery, like those presented by most of these guys.

How to stay safe? Put up a "No cold callers" sign on your door or window; say no to doorstep traders and don't engage with them; use a key chain and avoid answering the door.

Report the incident to the police if targeted, with a description and car reg if possible; these will be circulated nationwide in a jigsaw bid to catch the culprits, who are often on the move.

For bigger jobs, get a range of quotes and recommendations from friends based on experience.

Look out for yourselves, and look out for your neighbours. And, as Nick Ross used to say on Crimewatch: “Don’t have nightmares.”