From 1 April 2012, all remaining VAT-registered businesses – those registered for VAT before 1 April 2010 with a VAT-exclusive turnover of less than £100,000 – will also have to submit VAT Returns online and pay any VAT due electronically.

If you are still submitting VAT Returns on paper, HMRC strongly recommends you sign up to using the online service before April 2012, so that you have time to get familiar with the new service. Using the online service is quick and easy, and in most cases gives you extra time to submit your return and pay any VAT due.

Source : HMRC Website