When applying for British citizenship UK Visas and Immigration (UKVI) check many things before deciding whether or not to grant you your British citizenship. One of the things they look at is your ‘good character’, and part of this is your financial history.
Below is an excerpt from the government’s immigration policy:
6.2 Debt
The decision maker will not normally refuse an application simply because the person is in debt, especially if loan repayments have been made as agreed or if acceptable efforts are being made to pay off accumulated debts. However, where a person deliberately and recklessly builds up debts and there is no evidence of a serious intention to pay them off, the decision maker will normally refuse the application.