Microsoft declares war on Gmail with new Outlook service (and says customers will HAVE to use it)

Microsoft today launched an all out attack on Google in the email world with its new Outlook.com service.

The computer giant is to force users of its existing Hotmail and MSN email services to use the system, which officially launched today, in a bid to boost its uptake.

The firm has also unveiled a $90million ad campaign - but immediately came under fire for the attack on arch rival Google in the 'Scroogled' ad, which depicted the search giant's Gmail service as a 'snooping' service.

Microsoft says its new online service lets users easily send pictures to friends, and integrates Facebook and Twitter.

Microsoft is so confident it has the Internet's best email service that it is about to spend at least $30 million to send its message across the U.S.

All users of Microsoft's Hotmail sign up  and other email services operating under different domains such as MSN.com will be automatically converted to Outlook.com by the summer, if they don't voluntarily switch before then.