Mrs Underwood is known for her sons. Her eldest, Rory, 31, plays on the left wing for the England rugby team. Her third child, Tony, 26, plays on the right wing. They are the first brothers to represent their country in the same side since Arthur and Harold Wheatley in 1938. This was when people began to be curious about Mrs Underwood - about her background, her family life, her cushions. To breed one fleet-footed international rugby player could be put down to genetic fluke; to breed two looked suspiciously like craftwork. What did Mrs Underwood know? What were these kids on?
It didn't exactly dampen the media appetite for Mrs Underwood that she herself was a bit of a star-turn. During the England v Scotland game at Twickenham in 1993 - the game in which her sons debuted as an England partnership and both scored - the Grandstand cameras picked her out in the stands, ecstatic, performing what was either the world's first solo Mexican wave or some sort of slightly modified tribal raindance. The shot had all the markings of a TV set-up, as if a producer had sidled up to Mrs Underwood before the game and lisped: "Annie, darling - in the event of Rory or Tony touching down, can we bank on you for a nutty cut-away?" In fact, her actions were spontaneous. Mrs Underwood had no idea that she was on camera.
"I was jumping so high, I tripped and fell forward. A man behind me had a miniature television and he was trying to tell me, `You're on television.' I was shocked when the pictures appeared on the front pages of the papers. They were shot from down below, so I looked all teeth. Afterwards, when I went shopping, some people said, `Ooh, there's Mrs Underwood. You're so tall. We thought you were much shorter.' Also, because I had a big, fat coat on that day, people would say, `My, you've lost some weight.'"
It was quite a change of gear. One minute, she was going about her life, supplementing her widow's pension with a 10-hour week in the local knitwear shop; the next she was on Aspel with Mel Gibson and Julian Clary. Or almost: Mrs Underwood went along to the studios on the assumption that she was to be interviewed on the stage, like Mel and Julian. In the event, the producers stuck her in the audience and panned over to her for a brisk interlude - a quick introduction ("proud mum", etc), a couple of questions from Aspel and that was that. Still, the Aspel people had paid for a flight down from London, a night in a hotel and a few free taxis. "That, to me, was luxury," she says.
Mrs Underwood is a quick talker and you get the impression she brooks no nonsense. Like her sons, she seems embarrassingly fit and energetic. When we met last week, she had spent the previous evening at a Scottish dancing class and was preparing for the arrival of nine people that night for dinner.
She was born Annie Tan in Kuala Pilah, Malaysia, the oldest of seven children. The man she married, James Ashley Underwood, came from Middlesbrough, but worked for Harrison Lister Engineering on a posting to Malaysia, where Mrs Underwood was by then a typist. They went out together for four years and then married, producing, in the 1960s and 1970s, Tony and Rory and also Gary and Wendy, both of whom are now accountants.
Mrs Underwood describes Gary as "the one who the spotlight isn't on". Out-going and robust enough to deal with this, Gary was a promising schoolboy rugby player himself. It's possible that only his tallness precluded an astonishing international triple - in the wake of which Mrs Underwood would probably have had her own television series by now.
They came to England in 1976, bought the bungalow and installed their children at Barnard Castle school. Mr Underwood was promptly posted to Singapore, so for three years the rearing of the children was pretty much in Mrs Underwood's hands. When her husband returned, he started an engraving business near Bishop Auckland, providing the lettering for trophies, appropriately enough, and business signs. He died following a heart attack in 1982. He was 53. There is a picture of him on the sideboard in the sitting-room a month before his death, standing with the family in the snow, on their way out together for a meal. Rory is 17, Tony is 13 and still a thin boy.
Mrs Underwood carried on the engraving business for two years after her husband died, but then sold up. "I knew nothing about it. I just had to go in there, sign the cheques, pay the staff and go out delivering. The business at least stopped me from staying at home and moping. And people said, `Oh, you soon forgot your tragedy.' But it's nearly 13 years now, and I still have his photograph all over and certain music still brings tears to my eyes. There's never a day I don't mention his name. The other day, I said to Tony: `When I watched the television and saw you run from a different angle, I thought, by gum, you look like your father running.'"
According to Mrs Underwood, there were subtle signs early on that the children were going to excel as athletes. Rory, for instance, was born by Caesarian, two months early - an act of caution because his mother was suffering a thyroid problem at the time. But Rory weighed the standard seven pounds in any case. He was walking by 10 months and eventually learned, as a party-piece, to bend his feet under him and walk around on the joints of his toes. "That may be on my side of the family," Mrs Underwood says earnestly, before revealing that, in her youth, she was supple enough to sip sherry from a wineglass held between her toes. "Their strength, though, they got from their father."
They got given the cuisine of both their parents, too. Mrs Underwood raised them on Malaysian food as well as Yorkshire pudding and chocolate cake. "But English food was so much better then - the pork and the bacon you could buy tasted wonderful. Not like now, when it's all bland and tastes the same."
She was the first Asian to live in Barnard Castle. Early on, a resident caught sight of Mrs Underwood and remarked in her hearing: "Oh, dear, we're going to have a Chinaman come and live here". Mrs Underwood maintains this is one of only two direct encounters she has had with racism. The other occurred in 1983 when she went "down south somewhere" to watch Rory play for the RAF rugby team. "I arrived with my brother, my sister and the children and there was a comment: `Oh, my goodness, look at the boat people'.
"The children got a bit of name-calling. They don't look English, they don't look Chinese - they look in-between with a little bit more on the Asian side. And they were the only ones in the school. Rory and Gary used to get called Ching and Chong. They just braved through it. Then they became so popular, because of rugby, cricket and swimming. They were always winning."
Both boys were hot at football before they played rugby, particularly Tony. "I wish you could have seen him play," Mrs Underwood said, closing her eyes for emphasis. Their father had played for a club side in Kuala Lumpur (Mrs Underwood was "their Number One mascot") and coached his sons. "He taught them to run backwards and when he wasn't around, I told them to do the same - `Run backwards, like your father taught you.'
"I was strict with them as children," she says. "So was my husband. No monkey business with him. If they were naughty, he gave them a smack. I was strict in that, when they went to school, I wanted them to study first and not think about girlfriends and going out every night.
"I must admit, when they were young, I did smack them. In Malaysia, they even sell a cane, a bamboo thing. And that was a deterrent, because as soon as they saw me bringing that out, they knew that if they didn't behave, they would get the cane. I never liked them to answer back. You can reason, but not answer back. Maybe I'm a bit harsh, I don't know. Didn't seem to do them any harm."
Long before she was the eager parent in the stands, she was the eager parent on the touchline. Mrs Underwood would charge up and down to remain parallel with the action. She was sharply critical and remains so. She raises errors with them after the game, asks them sternly what went wrong there, what happened to their concentration. "Here's a question for you," she says to me at one point. "Name all the wingers who have played with Rory during his England career." Then she set about naming them. Mike Harrison, Chris Oti, Mark Bailey...
She has to fund her travel herself. Not for amateur-status rugby players the lavish, family-sized endorsements and bonuses doled out to footballers. (Tony works in the City, Rory is still in the RAF.) Mrs Underwood travels by coach to avoid the expense of the train, and relies on friends and friends of friends for her pre-match accommodation. "All through this time, I have stayed maybe just two or three times in a bed and breakfast. Much of the furniture here is still the same, second-hand furniture that my husband bought when we first came to this house. All my money is spent on following the boys - and I've been doing it since Rory went in for his under-16 school trials."
Reaching this year's World Cup in South Africa - a tournament in which the currently vital England side could do well - presents her with problems, but she is determined to make it. She recounts how the man at the travel agent the other day told her sheshould get sponsorship. "After all," he explained, "you're famous enough yourself now."