Those with refugee status and subsidiary protection may not apply for naturalisation as a British citizen until they have been in receipt of Indefinite Leave to Remain (settlement leave) for 12 months. They are subject to the same test of ‘good character’ as other applicants and must pass a ‘Life in the UK’ test and meet the requirements for English language proficiency. There is also a fee, which can be up to £1,330 (€1,537).
The requirements that a person be of good character specifically refer to applicants who previously entered the UK unlawfully i.e. through evading immigration control. This is despite policy that follows Article 31 of the Refugee Convention, acknowledging that sometimes it is necessary to enter a country unlawfully and be recognised as a refugee, and that the Refugee Convention requires signatory states to allow refugees to integrate.
190,175 grants of UK citizenship were made in 2021, of which 122,858 were from non-EU nationals.
 Home Office, Immigration and Nationality fees, available at: https://bit.ly/2PS2Ub0.