An impact assessment was completed in early 2016 which considered the changes being made as part of the Immigration and Nationality Fees Order (2016), the details of which can be found via the following link:
We believe the current policy which requires payment of a fee for all applications for British Citizenship, meets our international obligations.
Article 32 does not prohibit charging fees to stateless individuals. The current cost of limited and indefinite leave to remain for those who enter the UK on a five-year route to settlement is approximately £4,750. We feel that waiving these fees for stateless individuals up to the point of settlement, but requiring a fee upon becoming a British citizen is fair.
Taking this approach does not mean that the entitlement to apply for citizenship is lost, but rather deferred, until the fee is affordable. Our current approach allows us to fulfil our convention obligations whilst reducing the burden on the UK taxpayer; therefore striking the right balance for all.