Jeremy Paxman is not known for staying silent when vexed by an issue. Having finally despaired of what he says is the declining quality of Marks & Spencer underpants and socks, the Newsnight host finds himself a reluctant flag-bearer for the legions of British men being let down by sub-standard briefs.

Riled by his disintegrating undercrackers – he complains of a certain slackness in the gusset – Paxman wrote an email last week to the M&S chief executive Sir Stuart Rose to complain.

Something "very troubling" had happened, he explained, apologetically and somewhat ironically for a man whose interviewees would be forgiven for wearing reinforced undergarments. Marks & Sparks pants, the presenter said, "no longer provide adequate support". Pray tell! Too small? Too big? Do they get twisted inside his waders, as he stands waist-deep in an Oxfordshire river, fishing for salmon and trout?

Yesterday afternoon, after finishing his Sunday lunch, the BBC interrogator elaborated. "This is not just about the weak gusset issue," said Paxman. "It is about the separation of the cotton from the elastic, a very common problem. When I first noticed this some time ago I thought it might be a detergent problem. In fact, they are simply not being made to the same standards they used to be. I have spoken to loads of people, from Peers of the Realm to gardeners, all men who use these vital items of equipment, and we agree."

M&S insists that its male customers' complaints about underpants are at a "five-year low". A spokeswoman stonewalled gripes about manufacturing being outsourced to Asia as irrelevant "because the standards are the same everywhere". She added that the company employs a team of 70 in-house "technicians" to design its own brands of clothing.

"But the problem is not the design!" ventilated Paxman. "I've no problem with the design and never have. It's purely about the manufacture. It's very interesting they are being cagey about where they manufacture them now."

Paxman had considered his complaint a private matter and is irritated that his email was leaked. Bullish Sir Stuart has invited him to lunch in the next fortnight, telling the journalist to "bring your pants" and promising to have with him a goody bag of assorted undergarments for trial. Should make intriguing viewing for fellow diners.

"This was never supposed to be public," said Paxman, "but someone needs to speak up on behalf of British men, because we are being let down, both figuratively and metaphorically. We deserve more attention." Referring to M&S's marketing of its womenswear, he said: "I see Twiggy on the back of buses but I don't see any blokes there. This needs to change."

A BBC colleague, asked to speculate if Paxman was a Y-front man, said: "No, I'd very much guess boxers. He's a sharp dresser, quite immaculately turned out. He rarely requires much time in make-up and has very expensive suits. He'd go for something stylish under there. We're right behind him on this."

Good news may be at hand. There is, apparently, going to be a "revolution" in the world of men's ever-shrinking underpants. Out go chaps' boiled-grey grundies; and in come the seamless briefs already familiar to women to eliminate the VPL, or visible pants line. Good for tight suit trousers.

As Paxo says: "Even a sack of potatoes can be improved by a good pair of pants."

M&S shoppers give their verdict

Paul Page, London

"I don't buy my underwear here – the styles are usually too baggy. I like the waistband to show over my jeans and really, you don't want the waistband saying Marks and Spencer. However, my teenage sons wear M&S pants – the oldest because he's a student and they're quite cheap, the youngest because that's what his mother buys for him."

Patrick Brown, Washington, USA

We do have Marks and Spencer in the US, but I usually buy my underwear in John Lewis when I'm in London. I think generally speaking M&S's quality isn't good – it's quite disposable. I'm with Paxman on that one."

Phil Henes, London

"I buy most of my underwear here – I have bought it from other shops but those ones tend to fall apart in a few weeks – Paxman's wrong; the quality is better here."

Rita and Alexander Ghigo, Malta

"We always buy our underwear at M&S. It's good quality; you can wash it many times before it wears out. We have M&S in Malta, and we shop there, but it works out cheaper here."

Dave Smith, Stoke-on-Trent

"I stopped shopping here for a few years, but I've started coming again recently because they've introduced much better styles, more fashionable. I think the quality's pretty good."

Alan Ravenscroft, London

"I don't think about pant quality as much as Jeremy Paxman; I've got more important things to think about."