The annual Imaginate international festival of theatre and dance for children, which begins in Edinburgh tomorrow, is celebrated around the world and showered with critical bouquets on a regular basis.

This is down, in huge measure, to the extraordinary work over the last 21 years of the festival's director Tony Reekie.

Under Reekie's leadership the festival moved, in 1997, from Inverleith Park in Edinburgh into the city's theatres. It rapidly became the biggest, most prestigious children's theatre festival in the UK.

The secrets of the event's success are numerous. First, Reekie has curated the festival to the highest level, bringing shows of excellent quality from many parts of the world. More than that, however, while he has been on his travels, the director has been an advocate for Scottish children's theatre. Indeed, he even developed outreach programmes which enabled Scotland's children's theatre-makers to experience work abroad, thereby enhancing their own practice.

Scottish children's theatre is in fairly rude health, with various companies - from established group Catherine Wheels to relative newcomers Grinagog - creating work at a high level. It is no exaggeration to say that the most important figure in this scenario is Reekie. Shona Reppe, creator of numerous much-loved children's shows including the wonderfully inventive The Curious Scrapbook Of Josephine Bean, is one theatre-maker who attests to Reekie's significance.

"Tony has been pivotal in my career," she says. "He's been incredibly supportive of me, and represented me all round the world, in the context of talking about Scottish children's theatre more generally."

For Reppe, it is even more important for Scotland's children's theatre-makers to play Imaginate than it is to perform at the Edinburgh Fringe, the reason being that it attracts so many top international practitioners, producers and programmers.

"People come to Imaginate knowing that the quality of the work will be excellent," she says. "It represents so many different styles of children's theatre."

Andy Manley, whose acclaimed work includes the award-winning White (co-created with Ian Cameron for Catherine Wheels), is equally appreciative of Reekie's role, not least because he was a beneficiary of one of Reekie's international outreach programmes.

"I went to Denmark," Manley remembers. "I saw something like 23 shows in four days. That was a really mind-blowing experience for me."

For Manley, one of the greatest things about Imaginate under Reekie has been its artistic ethos. "It's about approaching children where they are, in terms of their real lives. That's what we expect of our art as adults; why should it be any different for children?"

Reekie takes his leave of Imaginate with a typically impressive programme. This year's offerings include The Bockety World Of Henry And Bucket, an acclaimed piece of comic theatre from Ireland designed for kids aged four- to eight-years-old. Spain's El Patio Teatro bring By Hand (A Mano), a promising work of object theatre about "love, small failures and a potter's wheel" for children aged six plus. There's classical drama, too, as London's Unicorn Theatre stages an adaptation of Shakespeare's Henry The Fifth for audiences aged eight and upwards.

Add top Scottish work, such as Imaginate commission The Lost Things, by Tortoise In A Nutshell theatre company and Oliver Emanuel, and it's clear that the festival has lost none of its vigour. The next festival director will be announced shortly, but we can be sure Reekie is leaving Imaginate, one of Scotland's great artistic success stories, in safe hands.

The Imaginate festival runs in Edinburgh, May 11-17. For further information, visit www.imaginate.org.uk