I do not have specific data on the average supermarket price of green apples in London. Prices can vary depending on factors like the time of year, quality/size of apples, and individual supermarket pricing. In general though:

• Green apples are usually among the more affordable types of fresh apples available in supermarkets.

• Typical prices per kg/lb are often in the range of £1-3/£1-4 depending on the supermarket and apple variety. Common varieties like Granny Smith apples often fall on the lower end of that range.

• Budget supermarkets like Aldi or Lidl may offer green apples at around £1-2 per kg. Large chains like Tesco, Sainsbury's, Asda are usually £2-3 per kg. Specialty greengrocers may charge £3-4 per kg.

• Expect prices to be a bit higher in central London shops versus outskirts due to real estate costs. Organic or specialty varieties will also trend more expensive.

• Seasonality impacts prices, with apples peaking in availability/lowest prices in fall months from September-November in the UK.

So in summary, a typical London supermarket price for regular green apples would likely be £2-3 per kilogram, but could range from £1-4 depending on specific factors. Let me know if you need any other details!