 "London")
Militants are increasingly turning to vehicle-ramming attacks, like the one staged near Britain's parliament on Wednesday, because they are cheap, easy to organise and hard to prevent.
Experts say the tactic of mowing people down avoids the need to obtain any explosives or weapons and can be carried out by a "lone-wolf" attacker without using a network of fellow militants - all lessening the risk of alerting security agencies.
"This kind of attack doesn't need special preparation, it is very low-cost, within anybody's reach," said Sebastien Pietrasanta, a French Socialist lawmaker and terrorism expert.
"It is often a case of
