A British tourist was among those killed in the attack on a museum in Tunis, Prime Minister David Cameron said Thursday, vowing to fight against extremists "with everything we have."

"We will not let terrorists undermine democracy," he said in a tweet.

A High Court judge on Tuesday barred a 16-year-old boy from leaving Britain amid concerns that he might follow his three brothers in joining al-Qaida-linked fighters in Syria.

In an extraordinary move, Judge Anthony Hayden made the teenager a ward of court following a request by the boy's local authority, saying he wanted to "keep this lad alive."

Prince Harry announced Tuesday he is to leave the British army after 10 years' service that has seen him fight on the front line twice in Afghanistan.

The 30-year-old said it had been a "really tough decision" to conclude his military service in June, but added that he was looking forward to a new chapter in his life.

British opposition leader Ed Miliband on Saturday set out five key election pledges and cast himself as the champion of a fairer Britain, two months ahead of May 7 national polls.

Miliband -- who has been dogged by an awkward public image since beating his more telegenic brother to win his party's leadership in 2010 -- accused Prime Minister David Cameron's Conservative-led coalition of favoring the wealthy and said a Labor government would be a country "for the many."

Turkey on Thursday said it had detained an intelligence agent working for one of the states in the US-led coalition fighting Islamic State (IS) for helping three British teenage girls cross into Syria to join the jihadists.

The surprise revelation by Foreign Minister Mevlut Cavusoglu appeared aimed at deflecting sustained criticism from Western countries that Turkey is failing to halt the flow of jihadists across its borders.

Around half the estimated 700 Britons who have gone to fight with Islamic State jihadists in Syria have returned home, The Sunday Telegraph newspaper reported. 

The weekly broadsheet's figures, in a story about a leaked draft of the Home Office interior ministry's new counter-extremism strategy, go further than previous estimates, of around 500 individuals leaving and 250 returning.

A man was arrested Sunday after spending the night wandering around on the roof of the Briish parliament.

The 23-year-old man, who has not been named, spent around eight hours on top of the Palace of Westminster in London after first being spotted late Saturday.

A chemistry teacher was jailed for six years in Britain on Thursday for trying to join Islamic State jihadists fighting in Syria, against the wishes of his family who desperately tried to stop him.

Jamshed Javeed, 30, one of a group of radicalized Muslims from Manchester in northwest England, was arrested in December 2013 as he was about to travel to the Middle East -- after helping his younger brother and three others make the same trip.

Plans for televised debates between Britain's main party leaders Wednesday collapsed into chaos after Prime Minister David Cameron vetoed the broadcasters' plans, barely two months before the general election.

The Conservative leader said he would only take part in one live broadcast contest involving at least seven party leaders, rejecting a head-to-head debate with opposition Labour leader Ed Miliband.

Britain's advertising watchdog banned an Israeli government tourism advert for suggesting that the Old City of Jerusalem was part of Israel on Wednesday.

The newspaper brochure showed a panorama of the walled Old City with the text "Israel has it all", and was ruled misleading by the Advertising Standards Authority (ASA), which said it implied the UNESCO World Heritage Site was part of Israel.