An arrest warrant against Julian Assange is still valid even though an investigation against him by the Swedish authorities has ended, a court has ruled.

Lawyers for the WikiLeaks founder had argued that the warrant should be dismissed because it had "lost its purpose and function" after the investigation over sex-related allegations was dropped last year.

Mr Assange has been living inside the Ecuadorian Embassy in London for over five years, fearing extradition to the United States for questioning over the activities of WikiLeaks if he leaves.

The outstanding arrest warrant dates back to 2012, when Mr Assange failed to answer bail associated with the Swedish investigation.

A warrant was subsequently issued by Westminster Magistrates' Court.

Lawyers for Mr Assange say the UK arrest warrant serves no legitimate purpose, but has been maintained anyway.

Senior district judge Emma Arbuthnot said in Westminster Magistrates' Court on Tuesday she was not persuaded that the warrant should be withdrawn. In front of a packed public gallery, the judge said the offence of not surrendering to bail was a standalone offence under the Bail Act.

She said: "On a straight forward reading of the section:

1. Mr Assange has been bailed.

2. He has failed to surrender.

3. If he has no reasonable cause he will be guilty of an offence.

"Once at court, the defendant would be given the opportunity to explain his failure to surrender and that is when Mr Assange would be able to place before the court his reasonable cause for failing to do so."