IT'S our sons' first real summer of freedom. They have taken to spending every spare moment out on their bikes with their mates. Apart from providing meals and clean clothes, J and I are officially redundant.

Entire days go by when all we see of our boys are brief flashes of colour as they dart into the garden, retrieve a water gun and hare off again. They gobble meals at top speed, fling down their cutlery and race out. After a decade of having them constantly buffeting around us, it's quite a shock to the system. Occasionally I'll ask one of my sons if he fancies a game of tennis or a bike ride with me. He'll look slightly uncomfortable, as if not quite knowing how to put it without hurting my feelings, and say: "Um, maybe another day." Which translates as: what, when I could be out with my friends? No thank you, mother.

I miss them hugely, even though I'm glad that they have close friends to run around with and aren't spending sunny days indoors, huddled over the PC. Apparently, last year more children were treated for games-console-related RSI than for injuries sustained falling out of trees. We have battled with our sons' rabid consumption of RuneScape, a horribly addictive online adventure game, and now the "issue" seems to have melted away.

That is, until one beautiful summer's evening when the boy-gang is heading out to do whatever it is they get up to, and one of our sons wants to stay at home. "Come on," I harangue him. "It's too nice to be stuck indoors." With a sigh, he heads out.

Daughter and I go to play in the park. It's one of those perfect, lazy evenings which stretches on and on, and no-one cares that it's way past bedtime. A junior orienteering group spills into the park, sets about negotiating a string course and gives my daughter a map. While she charges around, my mobile rings. It's J, telling me that our son, who just wanted a quiet time with the PC, has fallen off his bike and is now on a stretcher in an ambulance.

He has broken his arm. J spends the entire weekend in hospital with him. When I visit, the look in our son's eyes says "That's my whole summer gone". He no longer looks like the boy who returned emboldened after a school trip to France and seemed suddenly very grown up. He looks small, pale and frightened.

There are small consolations, like his fabulous James Bond-style hospital bed, which he is allowed to raise, lower and tilt by himself at the push of a button. He is thrilled by his X-ray and demands a print-out.

However, once he's home, reality kicks in. He won't be able to go on his Scout camp in August or even go out to play.

I know it's hardly unusual for a child to break a limb and that far worse things happen. It's just shocking how one tiny slip can transport you from a perfect summer's evening to being under general anaesthetic having metal pins inserted into your arm.

We are used to being able to make things better but he knows, as we do, that while his brother and pals run free, growing fitter and browner by the day, he will spend great swathes of the summer trapped at home.

We try to make things cosy for him with endless supplies of comics, books and DVDs (and RuneScape - lashings of RuneScape). I try to recall what cheered me up when I was sick as a child - tinned pears? Fuzzy Felt? - and work on my laptop beside him so that he doesn't feel lonely.

He rallies round, deciding that he'll design a board game, send it to a games company and make a fortune. He perks up even further when his pals pop round, but when they rush out to play again I can tell he knows he's lost his summer, and that no amount of Jammie Dodgers or comics can bring it back. Still, he reckons, that morphine was excellent.

Fiona's novel, Mummy Said The F-word, is out now (Hodder, £12.99)