Pope's visit a security headache
London - Pope Benedict XVI's state visit to Britain involved a major security operation even before five men were arrested on Friday on suspicion of plotting a "terrorist" attack linked to his trip.
Protecting the pope in four cities in Scotland and England at a mix of official and religious events threw up unusual challenges for British police, given that few state visits normally stray out of London.
The police commander in charge insisted before the visit that detectives knew of no specific planned threat against the pontiff.
"There is no intelligence to suggest any specific group will attack the pope," Chief Constable Meredydd Hughes said.
He said no previous state visit had involved so many different sites in Britain, but added that nobody wanted "a giant security operation with a religious service bolted on the back".
Benedict is visiting Edinburgh, Glasgow, London and Birmingham in central England on his four-day trip, which ends on Sunday.
Besides the pope, police would also have to protect those wishing to see him, as well as protesters, Hughes said.
Security measures evident
The estimated policing cost of the visit is between £1m and £1.5m.
The security measures have been evident since the visit began on Thursday.
Britain's top specialist public protection unit is being used, with armed officers deployed.
Black-clad police officers could be seen on the roof of the Palace of Hoylroodhouse in Edinburgh, Queen Elizabeth II's official residence in Scotland, as she welcomed the pontiff on Thursday.
Officers in high-visibility jackets lined the barricades as the pope and his entourage drove through the Scottish capital.
The pontiff has used his popemobile in Edinburgh, Glasgow - where it edged through crowds at the mass - and London.
In the British capital, sniffer dogs checked outside Westminster Abbey on Friday and unarmed police lined the popemobile's route.
The vehicle is flanked by a team of security guards in suits, with two at the front holding onto the vehicle.
The bulletproof glass windows can be lowered, as seen at the mass in Glasgow when Benedict kissed a baby held up by a pilgrim.
When not in the popemobile, the pontiff and his entourage sweep along in a fleet of cars, escorted by police motorcycles.
Police closed around 60 bridges on the road from Edinburgh to Glasgow as the pope travelled between the two Scottish cities.
When the pope visited a college in London on Friday - a few hours after the arrests - monks and nuns were frisked and had to pass through security scanners. Nuns' veils were inspected and rosary beads removed from handbags.
British police said the five men were held "on suspicion of the commission, preparation or instigation of acts of terrorism" when officers raided a business address in central London in the early hours.
Local authorities said they were street cleaners who work in the Westminster area where the pope spent much of Friday.
Vatican spokesperson Federico Lombardi said they were "totally confident" in the police.
"We are totally calm. The pope is happy with the trip until now and we go on with the same joy," he said.
For foreign visits, two Swiss Guards and members of the Vatican's security forces take charge of the pope's personal security, with the head of the Vatican team always at his side. The local police handle all other security aspects of the visit.
The baggage of everyone travelling on "Shepherd One", the papal plane, was manually searched and scanned. On board, Benedict sits at the front, with bodyguards preventing anyone from getting close.
The 83-year-old pontiff has been attacked during his five-year papacy.
In June 2007 a man leapt across a barrier in Vatican City and nearly mounted his vehicle and Benedict was pulled to the ground in December 2009 in St Peter's Basilica by a woman who cleared a barricade and grabbed his vestements.
His predecessor John Paul II survived an assassination attempt in 1981.