The last American nuclear bomber has roared away on its final sortie from RAF Lakenheath in Suffolk, to the relief of the nightjars and woodlarks which inhabit nearby Thetford Forest Park. Britain's largest lowland forest, it covers 50,000 acres and straddles the border between Suffolk and Norfolk. There are no "Keep out" signs and barbed-wire fences here - it's a people-friendly place complete with visitor centre, shop, cafe and picnic lawn (an ambitious feature, no doubt, in this weather, but much used in summer).

The use of space in the park is impressive. This may be a forest, but the plantations of conifers and broad-leafed trees are interspersed with areas of sandy heathland so there are plenty of open areas for outdoor activities. It's a particularly good place for families. For those with smaller children, there's a "Squirrel Maze" and an Adventure Play Course. And there are miles of circular, waymarked trails that can be explored by bike, on horseback or on foot.

A million people a year visit Thetford Forest, yet once you leave the main car park and head off into the unknown, the chances of becoming snarled up in a crowd of fellow hikers are minimal. If you crave only the company of squirrels, there are lesser known trails to follow, fanning out from a dozen smaller car park sites dotted throughout the forest. A map of these sites is available from the High Lodge Visitor Centre. Orienteering maps are also on sale. Adults are offered a choice of three levels, according to experience, and a mini-orienteering circuit, known as the Squirrel's Scamper, is Thetford's way of introducing children to the sport.

If you have resisted family pressure to fit a bike rack to the car, a range of mountain bikes, off-road tandems and trailer bikes are available for hire at High Lodge every day in the summer, and on weekends and in half-term weeks during the winter months. The cost of renting a child's mountain bike is pounds 5 per half day.

Thetford is managed on behalf of the state by Forest Enterprise, which has the delicate task of balancing the needs of recreational users with those of commercial forestry and nature conservation. The forest may be a pounds 3m a year timber-producing business but part of management time is spent in brainstorming ideas for imaginative events to increase the forest's appeal to visitors of all ages.

Events take place throughout the year and include: deer safaris, fungal forays, guided bike rides, murder mystery trails and nocturnal quests to see Thetford's rare nightjars.

Thetford's newly-introduced population of red squirrels may be in hibernation, but throughout the winter months there are family-orientated activities here to entice you to hit the TV off-button and line up the wellies beside the front door. These include Twilight Zone guided walks, a chance to see the forest at night, and Suzy Squirrel's Winter Nuts for the under- 10s, who are invited to become sleuths tracking down the squirrel's hidden store.

Our family has become very enthusiastic about Thetford Forest Park. On Sundays we tend to roam through the forest on our bikes. And a few weeks ago, at Hallowe'en we joined an 80-strong group for an evening of ghostly forest tales, with stage-managed sightings of spectral nuns flitting through the foliage.

There is no need to wait for an organised activity to get the best out of Thetford; you can always do as we did and import your own event. In August, we held our eldest daughter's 10th birthday party in the forest. Tea was consumed on the picnic lawn after an energetic six-mile bike ride. It should have been easy enough to follow the trail, but somehow we still managed to get ourselves lost, if only temporarily. After the ritual cutting of the cake, the girls disappeared for an hour of rope swinging in the adventure playground. The verdict from the birthday girl? "Brilliant fun ... total exhaustion. The best party I have ever had."

Thetford Forest Park is close to the A11 and is less than 45 minutes by car from Cambridge, Norwich and Peterborough. The High Lodge Forest Visitor Centre is open during the winter at weekends and in half-term weeks, and every day throughout the summer. Winter events at the park include story-telling (with tales of the forest) at 1.30pm on Sunday, 1 December, a mince pie walk from 10.30am on Sunday 8 December, and a barbecue with carol singing from 1pm on Sunday, 15 December. For more details call 01842 810271. Events cost from pounds 2 for an adult and pounds l per child.

For bike hire details, call Flinstone Adventures on 0589 100831.