Savers who apply for Ulster Bank's market-leading savings account could find their credit histories are altered, as the RBS-owned bank has undertaken identity checks which leave a record that other banks can see.

"Hard" credit searches are conducted by lenders when a consumer applies for some form of credit, such as a mortgage, loan or credit card, but it is highly unusual for them to be carried out on savings applications.

Ulster Bank, the Northern Ireland arm of the Royal Bank of Scotland group, said that in line with its terms and conditions, it was working with credit reference agencies to carry out fraud checks on customers which can leave a hard search on a customers’ credit record.

This was done "to keep customers and the bank safe and secure when customers are applying for new products," the bank said.

But these credit checks could leave customers with marks on their credit files which are visible to other lenders and could affect a person's ability to borrow in future. Other banks might perceive the credit check as a sign that the person has been applying for credit - rather than wanting to make a deposit. This could reduce their chances of being offered a credit card, for example.