Wash and lightly scrub the figs. Trim off any remaining stalk and cut a cross at their base like you would a Brussel sprout.
Mix the bicarbonate of soda with enough water to cover the figs in a large pan or bowl, add the figs and leave to soak overnight.
The next day, drain the figs, rinse them in cold water and weigh them. Make a note of their weight.
Place the figs in fresh, boiling water and simmer until just soft.
Drain the figs and dry them well on a tea towel.
Now make a sugar syrup using the same weight of water and sugar as the weight of figs you have - if you have 500g of figs, mix 500ml of water with 500g sugar and boil the syrup (without the figs) until it starts to thicken.
Add the figs and boil until the syrup is thick - this may take some time.
Now add 1 tablespoon of lemon juice per 250g figs and bring the mixture to the boil again before letting cool.
Bottle the figs in sterilised jars and cover with the syrup. If you find you haven't enough syrup make more (50/50 water and sugar) and top up the bottles before sealing.