British Prime Minister David Cameron on Monday condemned a new execution video by Islamic State (IS), calling it a "desperate stuff" from an organisation that is "losing anybody's sympathy".In the video released on Sunday, a masked IS executioner with British accent threatened to invade the UK and called British Prime Minister David Cameron an "imbecile," before executing five men who appeared shackled and dressed in orange boiler suits. They were accused of spying against the IS for the UK."It's desperate stuff from an organisation that really does do the most utterly despicable and ghastly acts and people can see that again today," Cameron said during a visit to east London on Monday."But this is an organisation that's losing territory, it's losing ground, it's, I think, increasingly losing anybody's sympathy, and this again shows what an appalling organization we' re up against," he added."They hate us not for what we do but for what we are - the fact that we are a successful, tolerant, democratic, multi-faith, multi-ethnic nation," the prime minister continued.Cameron also said that "Britain will never be cowed by this sort of terrorism"."Our values are so much stronger than theirs. It may take a very long time but they will be defeated."