After all, isn't this an organisation that caters for those in their twilight years?

I'd heard she was frum, so when this fashionably dressed, attractive, leggy brunette entered the room I was a little . . . non-plussed.

Now, here I must declare a sort of interest - I joined Saga recently, having discovered that it was not a society for the terminally retired or for bed-bound geriatrics.

If the d-g is anything to go by, Saga's members have more about them than many people a decade or two younger.

And yes, at 55, she's a Saga member herself - five years past the joining age - but that doesn't prevent her starting work each day at around 7.30am and not downing tools until 11pm or midnight at home.

"I'm working all the time," she says.

Ros positively beams throughout our lengthy interview, which leads me to remark that her broad smile must surely indicate that she is happier now than at any time in her long and distinguished career in finance.

It's obvious that after seven years as an independent consultant, offering strategic advice and consultancy to pension fund trustees, she could have had the pick of plum jobs in the finance sector, but she plumped for Saga just over a year ago.

Her last role included leading a campaign to achieve help for 140,000 people whose company pensions had been taken away from them by flawed legislation.

Today she works a six-day week, is Shabbat observant and at the end of a phone at all times when needed.

She confesses: "I couldn't survive without Shabbos."

Her prospective bosses at Saga must have had something of a shock when she arrived for interview.

They had certainly probably never previously encountered an Orthodox employee, let alone a female one.

But Ros insists: "It's not something that I make a big deal about.

"It's something that I made clear well before I accepted the role, or was even offered the role

"They had every opportunity to say, 'we actually want you on call seven days a week', and then I would have told them.

"It's not been a problem but it's a bit frustrating sometimes when I've been needed for advice, on yomtov actually."

But she insists that revealing her strong religious beliefs has never been a problem throughout her career, but being upfront about them is essential.

She adds that everyone needs a deputy because there are times when they are not contactable. No one, she stresses, is indispensable.

But she has attended job interviews in the past when she has pointed out that there are restrictions on her time because of her religious observance - "and it has been made clear that's not acceptable. That's actually illegal.

"It wasn't made explicit. It was made clear to me that it would be very, very difficult. Rather than, 'how shall we work our way round it', which is what everybody says".

In all her previous roles, Ros has always ensured that there is a deputy and therefore cover.

"I will make them aware that the time is well known in advance," says Ros.

"Having made it clear before you are even offered the job it's perfectly easy for them just not to offer you the job.

"I don't want to put anybody in a position where they feel uncomfortable about the fact that I'm religious."

Ros was brought up in a typical United Synagogue family. Today she belongs to the Kinloss Gardens congregation in Finchley, London.

Married to Paul Richer, a management consultant specialising in IT, she has three children.

Steven, 24, works on environmental policy at the Confederation of British Industry (CBI), Lisa, 19, is reading medicine at Cambridge and Emma, 18, is completing A levels at King Alfred School and intends to emigrate to Israel where she will first complete her army service

Ros's mother Renata, an artist, lives in Herzliya Pituach. She was a model and designer in her younger days.

Ros gushes: "I'm passionate about everything I do. I was in the fortunate position that I didn't have to take the job [at Saga].

"I had a wide portfolio of clients and interests that I loved anyway.

"I decided I would try this as a possible logical next step in my career. I really enjoy what I do. There are good bits and bad bits and lots of stress."

She admits that there are things she used to do which she misses, including working with a small business start-up.

But it's her opening remarks which lead me to ask Ros whether joining Saga had been altruistic rather than career-driven.

She explains: "All my life I've been involved in some way with older people."

Even her academic research, which led to a doctorate from the London School of Economics, involved investigating poverty and the incomes of the elderly, particularly looking at pension funds.

She's also managed pension funds and savings investments which are for use in later life - that is Saga-aged people.

"So," she explains, "given that Saga is a major financial services' company, you do need some kind of financial knowledge."

She also ran a campaign for 140,000 people who had lost their company pensions.

"I guess that broadened my work away from just the financial side towards ordinary people's lives, trying to join the two together - and Saga backed that campaign," she observes.

"I came in touch with them through that work. That perhaps showed that I really care about ordinary people and older people as well as being knowledgeable about the financial side.

"I was obviously a well-recognised public figure in terms of championing the cause of older people and standing up for what I think is right.

"Fighting the government is pretty scary. I couldn't turn my back on older people.

"Equally, from my side, I had to be very cautious and careful that if I was to tie up with any brand it was reputable and a good brand.

"There are a lot of financial companies I wouldn't dream of working for."

It was a case of obtaining value for money for people and "not just about making money".

"If I was only interested in making money I'd still be in the city. There are other important things in life."

Was Ros's move to Saga an altruistic one?

"Not necessarily altruistic," she responds thoughtfully, " but it broadens my opportunity to help people's lives.

"I didn't just come to Saga for the money. I was looking for something broader than that. My aim is to be in a position to make even more than a difference than I might be able to do do on my own.

"Saga is obviously very involved in financial services in the lives of the over-50s. It is a very important group that doesn't tend to fight for itself.

"They're the kind of people who have been used to just getting on with their lives, not making a fuss, making do, making the best of it themselves, looking after their families rather than shouting and screaming and protesting.

"I think the majority of the older generation don't tend to be organised. The proof of that is current policy."

Since the credit crisis started, she says, it encapsulates that what government policy has done is to take money away from older people and bale out younger people and bankers.

She adds: "Many older people either didn't know that or have just accepted it quietly.

"Look at what's happened to savers. Savers' income has been decimated and all we hear from policy-makers is how wonderful it is that interest rates are so low.

"I was warning in 2009, 2008 and all the time since I've been here that the result of current policy is going to be inflation, and if you couple that with low interest rates, it is the worst possible scenario for savers.

"The message from government policy is that you're a mug to save.

"Now who saves? Typically it's the over-50s. Who's trying to live on their savings? Typically it's older people.

"What's happened to their income? It's plummeted. What's happened to the value of their assets? It's been whittled away by inflation.

"Saga has always highlighted that their biggest concern is inflation followed by savings income. Much more concern than their health."

Ros's research showed that inflation affects the over-50s far more than the rest of the economy.

Anyone who has tried to live on their savings or bought an annuity with their pension savings has lost a fifth of their buying power, she stresses.

And she points out: "There isn't a typical Saga customer. We never think we have a typical customer, just like there isn't a typical 80-year-old or 50-year-old. There isn't a stereotype."

Saga's clients range from the very well-off to ordinary savers "who have saved a bit".

Saga, she says, tends to the higher income ABC1s, but there are lots of people in all social classes and all categories.

Saga, she adds, is now the biggest provider of domiciliary care.

But isn't Saga mainly for old biddies?

"It's for anyone in the second half of their life, " responds Ros, without hesitation. "Disparate groups - people who are active and not so active."

Saga even offers charity volunteer holidays which are almost almost akin to having the gap year members never had.

And its care business helps younger and older people because it is finding reliable carers for parents.

Ros maintains that retirement will become a process not an event.

"It's rid the idea that you're working full time, full pelt till Friday and then you're doing nothing on Monday.

"It's not healthy and it's a waste of resources. Not everyone will be well enough - not everyone at 50 is - thankfully most people are and more and more people are

It is essential that we overcome the stereotype of people counting down to retirement.

"And part of the problem here is that the individuals themselves take on the cultural norm but the cultural norm is going to change.

"I have no doubt that in 20 years time when someone has their 65th birthday you will not expect them not to be working

"I'm absolutely convinced of it, just as 30 years ago if you had gone to see a mum who had just had a baby you would not have asked her when she was going to be starting work.

"Now it's the norm. We are on the cusp of a revolution.

"I believe there are what I call bonus years - a whole new phase of life waiting to be grasped, a period maybe in your 60s or 70s when you are doing part time work.

"If we don't do it on the other side, if everybody continues to do what in the past everyone's been doing, what are they going to live on? It's a recipe for economic decline."

The reality, says Ros, is that a hugely growing proportion of the population is withdrawing from the labour force, not contributing to the economy and not having much money to live on.

At the same time, most people's pensions haven't delivered what they'd hoped for and they are expecting to be paid not to work.

"Well," says Ros, "the state pension isn't going to do much for them.

"What else are they going to live on? Whereas if they're thinking, 'what part time work can I be doing', 'how can I supplement whatever pension I've got' or 'I don't need a pension yet, I can keep working', it's much better for everybody.

"I can see it happening and I think Saga is quite well placed both to help people realise their own potential and these opportunities that are available and also to help them enjoy their extra leisure time or to help them improve their quality of life."

At present Saga deals with 'pre-retirement planning', but she would prefer it to become perhaps 'later life planning', involving both money, work and leisure planning and how to balance them all.

"We got very close to having an employment agency for over-50s but it ran aground on legal advice because of age discrimination," Ros reveals.

If it sounds like all work and no play for Ros, it's not.

She's a Tottenham Hotspur fan whose visits to matches at White Hart Lane are restricted to midweek and Sundays.

She owes her Spurs allegiance to her grandparents who ran a household shop in Tottenham Hale where her grandmother also undertook dry cleaning and alterations.

Ros also swims, although pressure on her time means that her four or five visits a week to the pool are down to once or twice, and she walks too.

She insists though that the only hobbies she enjoys are her children and family and she controls the youth workers and youth programmes at her shul as well as being a passionate supporter of Jewish Chaplaincy for which she has raised money.

She is also a patron of the One Family charity.

She says that "everyone comes to me" for yomtov and she loves having lots of people to her home on Friday nights.

Like the older people whose corner she so passionately fights, the thought of retirement seems to fill her with dread.

"As long as I'm fit and healthy, why would I want to do nothing?" she asks.

"There are loads of people who are not retiring. They don't know what they would do if they weren't working. They wouldn't know what to do if tahey didn't have any work to do.

"Not everyone wants to work full time, and that's not unusual. It's better to work part time and gradually reduce.

"When I was doing my PhD one of the things that struck me with the subject I was studying called sudden death retirement syndrome.

"There were people who gave up worked and suddenly died."

Her PhD in economics looked at poverty and income trends of the over-60s.

Could Ros remain at Saga for the remainder of her working life? "I'd rather not answer that one," she answers obliquely.

Has she any unfulfilled ambitions?

"In a work sense, not really. In a personal sense, I would like to see my children settled and happy and look forward to being a grandmother one day, but I'm not in a rush."

She would also like to travel to Australia and New Zealand.

But she concludes unsurprisingly: "I'm really lucky to have enjoyed what I've done."