Helensburgh's Lomond School has risen, like the proverbial phoenix, from the ashes of the disastrous blaze which destroyed the major front portion of the Victorian building in February last year.

Last month saw the splendid three-storey new building which houses forms from Transitus to S6 come fully into commission. It was largely designed by senior master Ian McKellar, an architect turned graphic communication teacher at Lomond, who also acted as master of works. It was probably a unique opportunity for a teacher to design a school.

Glasgow-based architects G D Lodge worked in close conjunction with Ian McKellar, and to them, he said, goes the credit for the handsome final exterior appearance of the building.

Lomond School, a co-educational day and boarding school, with 400 pupils from nursery to sixth form, was formed from the amalgamation of St Bride's School for Girls and Larchfield Preparatory School.

When fire broke out in the early hours of February 26 last year, headmaster Angus Macdonald was on school business in Germany. When McKellar got a telephone call informing him that the school was on fire, he could see the blaze from his home on the Rosneath peninsula.

By the time he got to the blazing building, he said, ''the fire had gone straight up to the maths classroom above the headmaster's room, and from there into the roof where it just went horizontally.''

Angus Macdonald takes up the story: ''The whole front part of the building was destroyed. We lost all the maths classrooms, the computing, English and geography classrooms, the staff room, all the administration block and some toilets. Very fortunately for us, we retained the two jewels of St Bride's, the school hall and the Bridesian Library (a panelled room gifted by St Bride's former pupils in the earlier part of this century).''

Despite such devastation to the working life of a school, not one day of teaching was lost. ''I think the motto was: 'We keep teaching' and we did,'' said Macdonald. ''We had about three classes in the hall, in passageways, in toilets even, and at Larchfield (formerly the middle school) there were many more senior pupils than usual.''

A month or so later, temporary Portakabin classrooms were installed in the grounds.

''Funnily enough,'' said Macdonald, ''I think the fire had an almost salutary effect on everybody. A real determination built up. The exam results at the end of that year were absolutely superb, we were fourth in Scotland on the quality of Highers. Pupils and staff were absolutely determined that it wasn't going to get in the way of the studies, there were emergency timetables and lots of midnight oil was burned.''

The creation of the new building and linking it into the remaining part of the school also gave Lomond the opportunity to revamp and upgrade some of its existing facilities. The total cost of these two phases of building and redevelopment was #2m.

The results are excellent. Catering facilities, which also serve the adjacent junior school and boarding houses, have been relocated from Larchfield - which has been sold - into the main school, giving an airy, light canteen-style self-service dining room.

Adjacent is a cafe-style social area for pupils, and above, in an open, galleried room, a sixth form centre has been made. Everywhere, there is emphasis on light, from a new atrium to the large north-facing windows of the art studio, while the old views across the Firth of Clyde, are even better.

Overall, said Macdonald, ''it has given us a huge improvement in facilities, particularly on the IT side. We now have a state-of-the-art building welded on to the core of the old 1879 Hall, it is very advantageous.

''Having Ian McKellar always available to us on the spot was invaluable, and being able to adapt to the changes that are inevitable, given the pace of change in education, has been a great asset.''

Disaster turned to advantage. A credit to everyone concerned in a remarkable team effort.