Do you hear that ticking noise coming from under the desks of young Aled and Sian in their Clwyd classroom? "It's a touch of wood beetle," says the Welsh National Assembly. "Don't worry. We've launched a schools refurbishment programme."
"That's not beetle," say the teaching unions. "It's a recruitment time bomb."
The condition of teacher recruitment in Wales is disputed, with prophecies of doom coming from one quarter and calm reassurances coming from another.
On the face of it, the picture couldn't be more different from the English scene. Welsh vacancies are few and far between, while English job advertisements increase by the week. Assembly figures show there were just 42 secondary and 26 primary school vacancies in Wales last week.
Although Welsh secondaries have shortages in the same subjects as English schools do, the situation is nothing like as acute. There is competition for jobs, especially at primary level. Applications have risen over the past year by 15 per cent in primaries and 7 per cent in secondaries. In Wales, house prices are lower than in England and the problems of inner city schools are fewer.
To prevent trainee drift, from September Wales will have the same teacher training incentives as England offers. Some are already in place.
The Assembly admits there are other problems. It has pledged pound;300 million over three years to refurbish dilapidated schools, especially rural valley schools, where outside lavatories are still common. Teachers in rural schools often have to cope with larger class sizes and wide age ranges. And the teaching population is ageing, with more than half of all teachers in Wales older than 44.
One of those who say they can hear that ticking is Brian Rowlands, who for 26 years was a headteacher in Wales and is now secretary for the Secondary Heads Association Wales. He believes policy should be based on what i happening now rather than on the past.
"Our members say they are now getting two or three applicants for jobs which would have attracted 20 or 30 a few years ago.
"The Assembly's complacency is based on figures which are out of date and on the fact that traditionally we have not had a problem. A lot of people have been very happy to live and work in Wales.
"But the number of applications has diminished across the board, from headships to newly qualified teachers. The feedback I'm getting suggests that it's getting harder and harder to find supply cover too.
"The difficulties are greater the further west you go, in Carmarthenshire, Ceredigion and Gwynedd, for example.
"Our ageing teaching population is a huge problem - a time bomb due to go off in about 10 years as it becomes harder to replace large numbers of retiring teachers. We didn't have the big exodus from the older end of the profession that they had in England a few years ago.
"Esteem is low and conditions of service are poor. What happens in teaching in England tends to happen in Wales some time later. We ignore that at our peril.
"We need the funding boost England has had in the form of the education action zones, excellence in the cities and specialist schools. Now we have a situation on the borders where schools on one side are getting extra funding and the Welsh ones aren't. Which schools are teachers likely to choose to work in? Whatever names you give the different funding schemes, they come down to money available on one side of the border and not on the other.
"And the profession needs the Scottish experience of a 35-hour week and less bureaucracy."
The National Association of Head Teachers Cymru, which represents most of the Welsh primary heads, has recently claimed that heads in some small rural schools are spending 80 per cent of their time teaching and has called for the Assembly to cap the number of hours a head can be expected to work. Many of its members, it says, are taking their administrative work home with them.