There are several reasons for the popularity of Towngas. The training scheme is widely admired for being well-structured and comprehensive. Many companies nurture talent only to see it leave. Towngas goes to great lengths to ensure its recruits stay.

'We manage to keep most of them,' Mr Yeung said.

When the company says it wants to develop future leaders, it means it. More than 100 of its top managers have been groomed under the scheme over the past 23 years.

Towngas has more obvious motivations than most to commit itself to the programme. First, as the only gas utility in town, it can hardly headhunt from rivals.

'You can't poach from the market,' Mr Yeung said, so the only alternative was to train.

At the same time, the company is expanding rapidly, most notably in the mainland. Having connected most of Hong Kong to piped gas (more than 1.5 million customers), the next frontier is joint ventures with state-owned gas enterprises. Partnerships have been established in 30 cities, and the company is talking to dozens more.

Compared with about 2,000 staff in Hong Kong, the mainland workforce already numbers more than 8,000 and continues to grow, with graduate trainees groomed for the front line.

'Without the graduate trainees, we could not expand at such a pace,' Mr Yeung said.

The key to successful retention, he said, was commitment to both career and personal development, as well as competitive starting salaries of about $16,000. Trainees are paid more than most to ensure they are financially stable.

'It takes two to tango,' Mr Yeung said. 'And if you pay peanuts, you get monkeys.'

But he believes it is the promise of long-term career development that attracts the cream of the crop.

While the programme grooms to manage, it goes well beyond familiarising graduates with corporate workings and sponsoring professional exams, depending on whether they are in the engineering, accountancy, finance or even human resources departments.

Because they are finely tuned as Towngas 'entrepreneurs', trainees inevitably lead operations in China.

'We want people to think commercially and challenge the status quo,' Mr Yeung said. 'They can go out and paint the town red. In the good old days, the traditional policy of utility companies was to look for solid citizens, but these days you need creativity. You need people who ask how things can be done better. We want people who make things happen.'

Training therefore extends beyond gas engineering to finance, insurance know-how, marketing, risk management, public relations and networking skills.

Social skills are also nurtured, from business dress code and table manners to mixing with company guests.

'[Trainees] are our long-term investment,' Mr Yeung said. 'We are buying the company's future, although it is true that some high-fliers fly higher than others.'

Since six-month attachments to China operations are an integral part of the two-year programme, trainees are encouraged to go out socially with visitors from Chinese partner companies.

'It's good for staff to understand the mainland social culture and practise their Putonghua,' Mr Yeung said.

These are changing times, and it is interesting to note that half the graduate trainees are women. 'In the past, engineers would always be men, but today's Hong Kong has one of the largest percentages of female engineers in the world,' Mr Yeung noted. 'Students and parents are a lot more open-minded these days.'

Once in while, the women engineers have unexpected experiences. Carol Lai, a 24-year-old graduate trainee, once had a problem getting a key to the ladies' toilet from a cleaner. The trainee was wearing overalls and a safety helmet. 'I had short hair, and she though I was a boy!' she laughed.

But Ms Lai is delighted she has been accepted for the scheme.

'The training is very comprehensive and I'm learning a lot. I was impressed that four senior managers interviewed me. Not many companies do that.

'Another big attraction is the opportunity to develop my career in China, just like a lot of trainee lawyers and accountants who are doing the same these days.'

As one of a handful of successful applicants, Ms Lai advises graduates to aggressively pursue the opportunity even after the interview.

'I kept calling and e-mailing to inform them of my degree results and ask if there was any decision. You have to demonstrate that you are really interested in a position. Don't just sit and wait for someone to call.'

Fast Track to the top

Training period: two years

How many people: seven or eight a year

Requirements: university graduate, outgoing character with strong communication and interpersonal skills, fluent in written and spoken English and Chinese, 'entrepreneurial' potential.

Bonuses: fast track to management, company commitment to career development, mainland attachment and subsequent advancement. At $16,000, one of the highest starting salaries of all graduate trainee programmes in Hong Kong.