Britain's largest retail chain Mark and Spencer customers email addresses have been hacked and the company has sent warning messages to many online customers who have supplied the store with email addresses, various media outlet reported.

On Tuesday, Epsilon, the world's largest permission-based email marketing Services Company that serves a number of American companies also had their mailing lists compromised, including the hotel chains Marriott and Hilton, as well as several banks.

We have been informed by Epsilon, a company we use to send e-mails to our customers, that some M&S customer e-mail addresses have been accessed without authorisation, the retailer said in an e-mail sent on BBC News on Tuesday evening.

We wanted to bring this to your attention as it is possible that you may receive spam e-mail messages as a result. No other personal information, such as your account details, has been accessed or is at risk,' it added.

The M&S security failure relates to a U.S. email company, Epsilon, which has been targeted in what has been called the 'biggest data breach ever'.

Epsilon, one of the largest email marketing companies in the world, sends more than 40billion emails annually on behalf of more than 2,500 clients.