What can be done to prevent Berlin-style attacks in cities?

The Berlin lorry attack on Monday that killed 12 people and injured 48 others raises a pressing question for security services across the world: what can be done to stop such attacks?

The carnage at Berlin’s Christmas market came six months after a 19-tonne cargo truck was deliberately driven into crowds celebrating Bastille Day in Nice, killing 86 people and injuring 484.

This seemingly new – and brutally destructive – form of terrorist attack is quickly becoming one that security experts fear the most: it can cause untold carnage and seemingly come out of nowhere. And there are obvious limits on the effect of practical measures.

On Tuesday, Berlin's police chief, Klaus Kandt, argued that bollards would not have prevented the attack. With "so many potential targets" – 2,500 Christmas markets in Germany and 60 in Berlin alone – he said it was impossible to reduce the risk to zero. But can they at least be made less likely? Yes, is the simplistic answer – but the measures to achieve that are varied, complex, and far from a panacea.

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Barriers in public spaces

The primary way is to erect huge, imposing barriers around vulnerable crowded areas: indeed, police chiefs in Berlin said on Tuesday they would now erect new barriers.

Ruth Reed, the head of the Royal Institute of British Architects' (Riba) planning group and its former president, said counter-terrorism officers in Britain would reassess the security of open spaces in the wake of the Berlin attack.

“There will be a degree of reassessment of public open space inevitably after Berlin – I think that will happen all over Europe, not just here,” she said. “The British approach has always been to put in a degree of protection, they may want to think about increasing it – but it can be done discreetly.”

The most obvious form of protection against a truck attack are large barriers, known in the architecture business as “anti-ramming landscape features”.

All US military and governmental buildings have “crash-and attack-resistant bollards” outside. The US department of state’s “anti-ram vehicle list” also lists several types of bollards to protect the perimeter of its embassies abroad. Some bollards are capable of stopping vehicles travelling up to 80km/h.

There are also innovative ways of protecting large crowds. Arsenal’s Emirates Stadium in London, opened in 2006, has been held up as a model for how physical barriers can be incorporated into a building’s design. Large concrete letters spelling out the word Arsenal at the stadium’s main entrance also act as a barrier to vehicles.

Concrete benches prevent a vehicle from weaving across the forecourt, and giant ornate cannons, which feature on the club’s logo, also form an obstacle for vehicles driving towards the stadium building.

“It’s not just the point of obstruction,” said Reed, who pointed out that measures including tight bends and restricted-width streets have been designed to prevent a large vehicle building speed before reaching a bollard or barrier.

Practical limits on security

Using a vehicle to commit a terrorist atrocity is not a new tactic. Apart from the Bastille Day attack in Nice earlier this year, Michael Adebolajo and Michael Adebowale first used a car to run down Fusilier Lee Rigby in London in May 2013 before stabbing him to death.

In June 2007, Bilal Abdullah and Kafeel Ahmed drove their Jeep Cherokee, loaded with propane canisters, into the glass doors of the Glasgow airport terminal. In the Israel-Palestine conflict, car-ramming attacks have become a regular feature, with Palestinian drivers running down Israeli soldiers and civilians.

While the security services across Europe have sophisticated systems to alert them to those acquiring weapons or explosives, getting your hands on a vehicle is easy.

In 2010, the online magazine Inspire, produced by al-Qaeda in the Arabian Peninsula, urged jihadis to target pedestrian-only locations and ram vehicles into crowds in order to "achieve maximum carnage". A 2014 propaganda video produced by the Islamic State encouraged the group's French sympathisers to use cars to run down civilians.

In the 2007 Glasgow airport attack, the concrete bollards outside the airport were credited with stopping the vehicle entering the terminal, though the terminal doors were damaged.

Prof Tahir Abbas, a senior research fellow at the Royal United Services Institute, said: "When you have an open event, something that's almost ad hoc such as a Christmas market, then the need to have greater security measures has become more pronounced in light of these events in Nice and now in Berlin," he said.

“Now designers and scientists have got the technology to create aesthetically pleasing barriers to prevent cars from ramming into buildings,” said Abbas.

“As part of that you have things like innocent flower pots outside buildings that are actually enforced with concrete and metal to prevent a truck from going over them. They are hidden and blended into the aesthetics of the building.”

“It’s like anything,” said Abbas. “You try to protect yourself from any possible risk, but there will always be something that creeps through.”

Guardian service