To fully appreciate the answer to this question, you should read the articles which I have linked in my other reply. Here are some relevant quotes (see articles for links):
"...For one, smaller countries such as Sweden are generally more susceptible to American pressure and bullying.
For another, that country has a disturbing history of lawlessly handing over suspects to the US. A 2006 UN ruling found Sweden in violation of the global ban on torture for helping the CIA render two suspected terrorists to Egypt, where they were brutally tortured (both individuals, asylum-seekers in Sweden, were ultimately found to be innocent of any connection to terrorism and received a monetary settlement from the Swedish government).
Perhaps most disturbingly of all, Swedish law permits extreme levels of secrecy in judicial proceedings and oppressive pre-trial conditions, enabling any Swedish-US transactions concerning Assange to be conducted beyond public scrutiny."
"The US has been seeking McKinnon's extradition from Britain for a full seven years and counting; O'Dwyer also remains in England and is the subject of a popular campaign to block his shipment to the U.S.; the NatWest Three were able to resist extradition to the US for four full years. These cases disprove, rather than prove, that an extradition demand from the US would be "swiftly complied with" in Britain. In contrast to the secretive Swedish judicial system, there is substantial public debate along with transparent (and protracted) judicial proceedings in Britain over extradition."
The UK has not only cooperated with the US to render terrorism suspects, but has cooperated with Libya to render dissidents to Muammar Qaddafi. There is no reasonable argument that Assange is safer in the UK than in Sweden.
"...For one, smaller countries such as Sweden are generally more susceptible to American pressure and bullying.
For another, that country has a disturbing history of lawlessly handing over suspects to the US. A 2006 UN ruling found Sweden in violation of the global ban on torture for helping the CIA render two suspected terrorists to Egypt, where they were brutally tortured (both individuals, asylum-seekers in Sweden, were ultimately found to be innocent of any connection to terrorism and received a monetary settlement from the Swedish government).
Perhaps most disturbingly of all, Swedish law permits extreme levels of secrecy in judicial proceedings and oppressive pre-trial conditions, enabling any Swedish-US transactions concerning Assange to be conducted beyond public scrutiny."
"The US has been seeking McKinnon's extradition from Britain for a full seven years and counting; O'Dwyer also remains in England and is the subject of a popular campaign to block his shipment to the U.S.; the NatWest Three were able to resist extradition to the US for four full years. These cases disprove, rather than prove, that an extradition demand from the US would be "swiftly complied with" in Britain. In contrast to the secretive Swedish judicial system, there is substantial public debate along with transparent (and protracted) judicial proceedings in Britain over extradition."