Vodafone has revised their Pay as you Go internet tariffs. The previous charge for internet rate was 2p per 10KB which has now been increased to 4p per 10KB. The new charges are with effect 20th June 2014.
When visiting the Vodafone website there is nothing mentioned about the price increase. This information was sent via SMS, so it could be that the website has not been updated, but its to be believed that the price change has most probably taken place, as Idea have already increased their data pay as you go data charges at 4Kb per 10KB, so Vodafone are just following the trend.