Winter vegetable and bean soup with spicy sausage

225g (8oz) rindless streaky bacon, cut into 5mm (1/4 inch) lardons

2 tbsp olive oil

225g (8oz) onions, chopped

300g (10oz) carrot, cut into 5mm (1/4 inch) dice

215g (7 1/2oz) celery, chopped into 5mm (1/4 inch) dice

125g (4 1/2oz) parsnips, chopped into 5mm (1/4 inch) dice

200g (7oz) white part of 1 leek, 5mm (1/4 inch) slices thick approx.

1 Kabanossi sausage, cut into 3mm (1/8 inch) thin slices

400g (1 x 14oz) tin of tomatoes

salt, freshly ground pepper and sugar

1.7 litres (3 pints) good homemade chicken stock,

225g (8oz) haricot beans, cooked *

For the garnish:

2 tbsp parsley, freshly chopped

extra virgin olive oil (optional)