Place the shredded rind into a non-reactive bowl, cover with 375 ml of the water and leave to steep for 24 hours.

Chop the flesh of the peeled mandarins, the unpeeled mandarins and the lemon, and place the fruit into a large non-reactive bowl, cover with 750 ml of water and leave to steep for 24 hours.

The following day, put the fruit and liquid into a large pan and add the remaining 500ml of water. Bring to the boil and simmer gently until the mixture has reduced by one third.

Meanwhile, place the shredded rind and liquid into a saucepan, bring to the boil and simmer gently for one hour. Strain the liquid from the peel, adding the liquid to the large pan of simmering fruit, place the peel into a container, cover and refrigerate.

Once the mixture in the large pan has reduced sufficiently, remove the pan from the heat, and carefully ladle the mixture into a jelly bag set over a large bowl. Leave to drain for 24 hours (don't be tempted to press the mixture to force the liquid through).

Measure the strained liquid and pour it back into the clean pan. For every 600 ml (1 pint) of liquid, measure 450g of sugar and add it to the pan, along with the reserved shredded peel.

Place pan over a gentle heat, and stir until the sugar has dissolved completely.

Increase the heat and bring to the boil. Boil rapidly for 20 minutes and then start testing for setting point (see notes below).

Pour into jars, seal and label.