Bosses at a Skipton Building Society-owned finance company have moved to reassure their customers after a laptop containing the details of up to 14,000 customers was stolen.

Although no bank details of customers of Skipton Financial Services (SFS) were included on the computer, information including names, addresses, dates of birth and National Insurance numbers was.

The theft occurred last week when a computer belonging to an external IT company working for SFS, Moore Stephens Consulting, was stolen. It contained information regarding investors in the Fidelity FundsNetwork (CORR).

The incident follows a spate of losses of personal data. Two CDs containing details of 25 million child benefit recipients were misplaced in the North East last month, followed by details of three million learner drivers which went missing in Iowa, USA.

Bosses at SFS say they acted to protect the customers concerned immediately upon learning of the stolen computer and that increased security measures have been placed on all of the accounts affected.

Each customer affected is to be issued with new account numbers and offered 12 months' free credit checks and alert services through the credit reference agency Callcredit.

SFS added that it had yet to be made aware of any fraudulent activity on any of the accounts concerned.

Simon Halt, the managing director of SFS, said: "While neither SFS nor Fidelity FundsNetwork were responsible for the loss of this laptop, both have taken all steps they can to mitigate any risk to their clients. Immediately SFS was alerted to the problem, it put a security block on all accounts concerned. The company has now sent letters to all of the customers affected to assure them their investments are safe.

"SFS has notified the Financial Services Authority and the Information Commissioner's Office of the situation and is currently working with Moore Stephens Consulting Limited both to investigate how this incident occurred and to ensure it does not happen again."

Robin Walker of the Financial Services Authority said: "We have been informed of this by Skipton Financial Service and are aware of what happened."

SFS is a wholly-owned subsidiary company of Skipton Building Society and employs more than 250 people.

Anyone wishing to contact SFS can do so on 0800 137832.