OXFORD University has admitted hiring investigators to sift through information about former students' finances. 

The institution is among 24 in the Russell Group who reportedly paid 'wealth screening firms' to find rich alumni to target for donations. 

Claims were revealed today in the Daily Mail, which states Oxford screened 199,369 records to assess alumni's wealth.

It is said to have used companies including WealthEngine, which describes itself online as 'providing wealth intelligence solutions to help fundraising, marketing and business development'.

According to the newspaper, which gained details under the Freedom of Information Act, universities 'secretly' stockpiled sensitive information on former students' incomes, investments, pensions and value of homes.

The university this morning denied that it tried to hide its use of wealth screening firms, and said alumni were made aware of its data protection policies.

The Information Commissioner's Office has now launched an investigation into the universities.

If it finds any trawled personal data without consent, it could issue hefty fines.

A statement issued by Oxford University said: "We have used wealth screening firms to support our efforts to raise money for our research and teaching objectives.

"It is a tiny part of our fundraising activity and the vast majority of the screening happened at least eight years ago.

"We have not tried to hide this – every email sent to alumni has a link to our data protection statement, which clarifies that our development and alumni relations system may be used for fundraising and hold donor status and wealth assessment information.

"For many years, all alumni have been able to opt out if they do not wish their data to be used in this way, and we would never sell their data to external partners.

"We are committed to transparency in the use of our data and we will continue to review our data protection statement to see if we can make it clearer.

"We are proud of the results of our successful fundraising campaign – it has funded thousands of students from all backgrounds to study at Oxford, and research which has transformed the lives of people around the world."