The crowd at the last Ploenchit Fair to be held in the British Embassy grounds, in 2000, was just over 23,000. That's a bigger attendance than for the Fulham-versus-Everton game a fortnight ago - and a respectable turnout even for a rock festival.

Then came 9/11. Security concerns made the embassy off-limits. And that was that.

"In truth," says Carolyn Tarrant MBE. "We were outgrowing the embassy. Lovely as it was, we were bursting at the seams. We'd become a victim of our own success."

We are sitting in the headquarters of the British Community in Thailand Foundation for the Needy (BCTFN), just opposite the Villa supermarket. It's another mad day in the office. The phones never stop ringing, people are coming in and out and Carolyn is cajoling, charming and hassling stall-holders and companies about their promises and commitments.

Time is short and there are a gadzillion things to do before the 60th Ploenchit Fair opens on Saturday.

From quaint "tea on the lawn" beginnings as a charity do at the British Club in 1946, Carolyn has now run 27 of them - and in many ways is the Ploenchit Fair. It's a fact recognised by her being awarded the MBE (Member of the British Empire) medal in 1995. Carolyn does have staff to help, but I noticed that everyone who calls only really wants to speak to her.

A large map of the fair is spread out on her desk, like a battle plan. It shows which stalls go where, the electricity requirements, the bunting to be hung, the parking, the security, the space required.

"Dame" Carolyn, as she is affectionately called by the charity members, is working the phones while digging out a cheque for Bt200,000 that will equip an entire school with desks, chairs and equipment in Chiang Mai.

The BCTFN has also helped establish a new foundation to encourage disabled people. "In the workshop we have disabled people making wheelchairs for other disabled people," she says. Neat idea.

What makes the BCTFN unique is that it doesn't hand over a single baht of cash. A charity must submit its needs in writing. The committee then considers it at the monthly meeting and thoroughly checks out the quote, the price and receipts. They then visit the project and oversee what has to be done. Nobody creams off anything. It's open, audited and very efficient.

"Since we became a foundation in 2000, we've managed to give Bt34 million to around 30 charities," Tarrant says. "We do not give cash and prefer to give to projects that enable them to become more self-sufficient. And consistency is the key. Funding goes on throughout the year - and every year the fair gets bigger and so helps more people."

With a marvellous no-nonsense approach, delightfully free of airs and graces, Tarrant is forthright and funny - essential qualities for a demanding job. Other mortals would be tearing their hair out under the bombardment of details and delays and last-minute complexities of organising an event this size.

Occasionally she does need to assert herself. There are many promises and pledges made in the world of charity, and some need to be chased up. "I can be a right little Hitler when I need to be," she grins.

And Tarrant attracts loyalty. Most of the stall-holders have been the same for 30 years. Many who came as children with their parents now run the stalls themselves.

What motivates her to continue as president of the foundation committee after 27 years at the helm?

"There is the immense satisfaction of seeing what a little bit of money can do to change people's lives here. Sink a new well in a village and 400 people are affected. As for the annual fair, one of my greatest pleasures is seeing other people enjoying themselves. The whole aim is to make money for charities and have fun at the same time. I think everyone senses this - so the day always has a special ambience."

Indeed it does. Apart from meeting old friends, you see people you haven't seen for ages. You also see people you only see once a year. Not that it matters if you can't remember their name. They can't remember yours either.

As I get up to leave, the phone trills once more and Dame Carolyn turns to give it her full attention - and another piece in the mad jigsaw is dealt with. She waves and winks. A true Dame without borders.

Ploenchit Fair is at BEC-Tero Hall this Saturday. Gates open at 10am. Entry fee Bt100 and Bt20 for children.

Roger Beaumont

The Nation