Put 1kg of lemons in 2 litres of water.
Get the heat on high with a lid on until it starts to boil
Boil for 45-90 minutes until lemon skins are tender (easy to puncture with fork)
Take lemons out from water and chop as fine as you like (leave pips in for now they will help set the marmalade)
Get the heat back on, add the 2kg sugar and chopped lemons to hot water
Boil and reduce for half an hour then remove pips with a spoon
Have a saucer in freezer, when reduced, put a little on the cold plate. Leave for one minute. If it wrinkles when you push with your finger, it's ready to get into sterilised jars
About this many jars is enough
Boil jars and lids in water sterilise.