The former CIA worker who leaked secret surveillance details to the Guardian is a hero according to two in five people polled.

Edward Snowden, 29, who is currently on the run from the American authorities, sacrificed himself for the public good according to 41% of respondents.

An Opinium/Obsever poll further found that 43% also believe Snowden has done something "brave and should be heard, not prosecuted". One in five (23%) disagreed.

On Saturday, in a sign of public support for the American, a demonstration took place outside the US consulate in Hong Kong. Snowden has not been seen since leaving a hotel there last Monday.

Hundreds marched to the consulate where they delivered a letter addressed to consul general Steve Young. They also urged the city's government not to extradite Snowden who has admitted to leaking documents said to show how the US National Security Agency obtained direct access to the systems of Google, Facebook, Apple and other US internet giants.

A PowerPoint presentation leaked to the Guardian by Snowden appears to show that the NSA access is part of a previously undisclosed program called Prism, which allows officials to collect material including search history, the content of emails, file transfers and live chats. The presentation claims the program is run with the assistance of the companies, however Facebook and Google have denied knowledge of Prism.

The new poll has 45% agreeing that Snowden has broken the rules of his employer, the US contractor Booz Allen Hamilton who work with the NSA, and should be reprimanded. One in five (22%) disagreed.

However, when asked whether they agreed with the statement that Snowden had committed a crime and needs to be prosecuted only 30% agreed compared with 37% who disagree.

Opinium Research carried out an online survey of 1,942 GB adults aged 18+ from 12th to 14th June 2013, Results have been weighted to nationally representative criteria.