The cost of becoming a British citizen is now more than five times the estimated cost of processing an application, according to an analysis of the latest Home Office figures.
Applicants seeking naturalisation must pay £1,709 under the latest fee structure, compared with an estimated administrative processing cost of £324. Successful applicants must normally pay a further £130 for a citizenship ceremony, bringing the overall cost of becoming a British citizen to £1,839.
The figures have been highlighted by the Institute for Public Policy Research (IPPR), which has warned that the high cost of citizenship could place the process beyond the reach of some long-term residents who have already built their lives in the UK.
The Home Office increased the naturalisation fee by 6%, with the latest figures showing a significant gap between what applicants pay and the department's estimated administrative cost.
The cost of British naturalisation is considerably higher than that charged by other major developed economies.
At £1,709, the UK application fee is more than three times the next highest fee among G7 countries cited in the analysis. Naturalisation in the United States, for example, costs the equivalent of around £562.
For many migrants, the citizenship fee comes after years of other immigration-related expenses.
Before reaching the point of applying for British citizenship, applicants may already have paid thousands of pounds in visa fees. Many are also required to pay the Immigration Health Surcharge, currently £1,035 per person per year for those subject to the charge.
The combined financial burden means the eventual cost of securing British citizenship can be substantially higher than the naturalisation fee alone.
Nearly all successful applicants must also attend a citizenship ceremony. The ceremony has to be booked within three months of confirmation that citizenship has been granted.
Steve Valdez-Symonds, refugee and migration rights policy lead at Amnesty International, criticised the continued increase in immigration and nationality fees.
He said successive governments had used high charges to shift the cost of operating the UK's immigration system from taxpayers to migrants, including people who may already have paid taxes and incurred legal expenses.
Valdez-Symonds also argued that migrants could end up bearing the financial consequences of problems within the immigration system, including delays and administrative errors.
Imran Hussain, director of external affairs at the Refugee Council, said citizenship had historically been encouraged as an indication that someone had successfully integrated into British life.
He warned that increasingly high costs could make citizenship inaccessible to some refugees who have established long-term lives in the UK.
The IPPR similarly argued that high fees could leave some people who have lived in Britain for many years without full participation in the country's political and civic life.
The debate comes as Home Secretary Shabana Mahmood faces pressure over proposed changes to the settlement system.
Mahmood announced plans earlier this year that could require many migrants to wait 10 years before qualifying for settled status, rather than the current five-year period applicable to many routes.
The proposals have faced opposition from some Labour MPs, and Mahmood is expected to consider exemptions and other changes to the proposed indefinite leave to remain rules.
Against that backdrop, the IPPR has called for a broader approach to immigration that places greater emphasis on settlement, integration and eventual citizenship.
The thinktank argues that Britain should become less reliant on a system centred on temporary migration and instead establish clearer routes for people who intend to make the country their permanent home.
It has also called for citizenship fees to be brought much closer to the actual administrative cost of processing applications.
Former Labour Home Secretary David Blunkett has backed calls for greater emphasis on citizenship and civic participation.
In a foreword to the IPPR analysis, Blunkett called for citizenship and democracy to be introduced to the school curriculum next year rather than waiting until 2028.
He also proposed allowing people on authorised visa or resettlement routes to qualify for indefinite leave to remain earlier if they complete English-language courses and demonstrate a commitment to their local communities.
Blunkett argued that the journey towards naturalisation could be accelerated by giving long-term residents opportunities to demonstrate their contribution to the communities in which they live.
The IPPR has separately recommended replacing the existing Life in the UK test with a citizenship course and assessment covering community life, British institutions and shared values.
Marley Morris, who authored the report, said a fair immigration system should treat new migrants as potential citizens and provide an affordable route towards permanent membership of British society.
He argued that the current citizenship process remained largely bureaucratic while the cost could place naturalisation beyond the means of many applicants.
The Home Office rejected the suggestion that the government profits from immigration and nationality fees.
A spokesperson said the department did not profit from the charges and explained that income from fees set above the direct processing cost helped fund the wider migration and borders system.
The spokesperson also said British citizenship was a privilege and argued that people benefiting from the UK's migration and borders system should contribute towards its operation.
The dispute places the £1,709 naturalisation fee at the centre of a wider debate over who should bear the cost of Britain's immigration system.
For migrants who have lived, worked and established families in the UK for years, the financial barrier comes at the final stage of a process that can already involve substantial visa, health and legal costs.
Daily Dazzling Dawn understands that the question is therefore not simply how much it costs the Home Office to process a citizenship application, but whether the current fee structure provides a fair and accessible route for long-term residents seeking to become British citizens.