You need to get rid of as much of the rubble as possible and then get some good top soil before you can even think of having a lawn... and don't buy the top soil from cowboys or you will end up with rubbish!

Moon Grower's right - I'm afraid you need to excavate all the buried debris they've left behind first. If you find you need topsoil, make sure you order top grade - most of its awful stuff, motorway spoil full of weeds. If you can cope without it, do, but add plenty of well composted materials to the soil after you've cleared it of debris and weeds, as much as you can afford to buy.

Having spent quite a few years creating lawns from junk yards for various customers the rule of thumb should be.

Clear all of the rubble, make the area as smooth as possible - give yourself a fighting chance.

You will probably need to import soil but a tip for not being being able to afford top grade is to mix sub grade with sharp sand but ensure you sieve well to remove oversized stones and rocks.

The sharp sand will give good drainage to the lawn when the grass has taken.

An aggregate bag of sharp sand - 1 tonne approx - costs around £35 currently whereas a tonne of top soil can be anything from £15 - £50 per tonne depending upon where you live.

Good luck