VAT = 20%
Alcohol duty on a 75cl bottle of fizz with a ‘Champagne Cork’ = £2.32 (ex VAT)
Therefor the tax on a £10 bottle of fizz is £4.32, which leaves £5.68 for the merchant, transporter and producer.
There are higher ‘fixed costs’ involved with making a sparkling wine than a still wine. Specialist equipment is required, the bottle must be of a higher specification and is heavier (this means higher shipping costs) and requires a secure closure which is usually a fanned cork secured with wire, also more cost than a still wine closure.
Please bear in mind how little will have been spent on the ‘drink’ should you chance a sparkling wine for under £10.