Unless the lawn is far more weeds than grass I'd wait until it starts growing and mow it weekly for a few weeks. You'll probably be surprised at how good the results can be.

It really depends on how bad it is . You could dig it up and if you want a quick result lay rolls of turf. Water them in well and give them a few weeks to settle down before your son plays on it. Or wait till spring when the grass starts growing again and apply a weed and feed treatment and see how that does. As Anchorman says, it may revive.

personaly id dig it over myself so you have a clean slate then you can have a lawn , plants , boarders just wear you want them .

Trouble with reseeding is you can't use it normally for 3 months after it's germinated - the grass is not tough enough to withstand normal use, specially not a child. If you have a mower, you'll find the vast majority of weeds disappear once you start cutting regularly - the only ones left will be the rosette type, such as dandelions. If there are nettles or brambles, best to dig those out first though. Depending how bad it actually is, that might be the best and quickest route to having some usable grass for your child. If its got potholes, you can fill those in with soil and sprinkle a bit of seed on top - small areas of seed will be okay.

i would turf it for instent results but these are all good options . you mite like the shape of the lawn as is and as bamboo sais it mite not be to bad . definatly the easiest and cheapest way .

I would start by strimming (if it's that long) and then just keep mowing. A lot of the weeds won't like this and will die, the rest (daisies etc) are great and as long as they are green...who cares! It will be more resilient to football matches too! Clear any rubbish and cut new edges and it will make a big difference.

you got nothing to lose and realy it would need some work anyway even if you were to get it returfed .

most prefeshional garden designers love to start from a blank canves . im an amater excuse my spelling garden designer and sculpter/artist and it makes perfect sence to me .

I know it's been a while but just wanted to say thank you for all your answers. They gave me hope :-) I did what you suggested and just cleared the rubbish, and then waited for the spring growth to hit in. I mowed it a couple of times since then and the garden looks much better than before!

You tackled it at the right time - its amazing what happens when you clear the debris and just mow regularly.

brilliant im glad its working out for you .