I want to apologise: I have let myself down. I let others down too, and I’m sorry. Not because, Matt Hancock-style, I breached social distancing guidelines with a steamy office affair — but because I missed the scoop. I was sent a compromising picture of the then health secretary and his mistress almost a week before the Sun newspaper sensationally revealed their relationship — and I did not believe it was him.

Having never knowingly undersold my ability to break big stories, this is embarrassing to say the least. Over the years, my scoops have led variously to the jailing of a cabinet minister (Chris Huhne); the resignation of the UK’s ambassador to Washington (Sir Kim Darroch); awkward ‘questions to answer’ for William Hague (after I revealed the married former Tory party leader was sharing a hotel bedroom with a young male aide); the embarrassment of Prince Andrew, when I obtained a cache of his emails; and yes, that notorious story about a prime minister and a pig. (Say what you like, but only the shock departure of teen heartthrob Zayn Malik from the band One Direction attracted more tweets and memes that year.)

So how did I miss this one? Here’s what happened. On the morning of 20 June I was leafing through the Sunday newspapers when I received a message from an important contact. ‘Good morning. This might brighten your day, I have a guy who says he has incriminating footage of Matt Hancock,’ he wrote breezily. Accompanying the text was a grainy image, no bigger than a postage stamp, of a man in a suit, leaning forward to embrace a raven-haired woman in a figure-hugging dress. ‘What to do next?’ the message asked.

Frankly, it looked nothing like Matt Hancock. Even now I know it’s him, it still doesn’t. Crooks and oddballs send journalists weird stuff all the time. My contact — a highly successful entrepreneur — was certainly none of those things, but he seemed an unlikely recipient of this kind of kompromat. I peered at the picture. Could it really be the health secretary? I didn’t think so.

I only had the one poor-quality screen grab (not the video that would later be released) and no information about the original source. The picture had been sent to my contact via an untraceable ProtonMail account. Moreover, the pandemic has sent all manner of conspiracy theorists and pranksters into overdrive, creating perilous working conditions for journalists. Private messaging groups on social media are awash with nonsense about Bill Gates’s secret agenda to microchip the human race. There are umpteen very convincing–looking fake government documents doing the rounds (all of which, annoyingly, I will now have to take more seriously — just in case I get it wrong). So my default position when it comes to these tips is to be ultra sceptical.

Over the years even the most brilliant journalists have fallen victim to hoaxes, with devastating consequences. Piers Morgan was fired as editor of the Mirror in 2004, for publishing pictures purporting to show Iraqi prisoners being tortured by British army soldiers. The photos turned out to be fake. As editor of the Sunday Times in the 1980s, Frank Giles published the ‘Hitler diaries’, which turned out to have been written by somebody else. Giles had done due diligence, drafting in the distinguished historian Hugh Trevor-Roper to authenticate the material, but that did not diminish the huge embarrassment when it turned out they were wrong.

It seemed vanishingly unlikely that the extraordinarily busy and apparently happily married health secretary would be frolicking in his office with a foxy brunette. Also, there was something funny about the image, which appeared to show an extra hand on the woman’s back. ‘That’s not Matt Hancock,’ I sniffed. ‘Wrong hairline? Looks more like [A.N. Other Tory MP whose private life is of no public interest]. Also, the picture is very weird. Looks as if it’s been doctored — those aren’t his arms round her waist? If he has more footage, let’s see it?’

My contact agreed that his source was ‘probably a chancer’, but said he would see what else he could get. ‘No rush,’ the original source said when they discussed arrangements for viewing the full video — and then he or she hotfooted it to the Sun.

So mea culpa. Like Hancock, I’m an idiot. My contact, an anti-establishment figure with a dim view of politicians in general and a particular disdain for the architects of the lockdown policy, would have relished his part in exposing Hancock’s hypocrisy. I let him down. And I’m left hungrier than ever for the next political scalp. This was the one that got away. Note to other politicians with skeletons: the next one won’t slip through my grasp.