Security stepped up at UK ports
Security has been stepped up at UK ports and border controls following the terrorist atrocity in Paris.
More cars and lorries are being searched on cross-channel routes, and a more visible security operation is in place at the Eurostar terminal in Paris at Gare du Nord.
Downing Street said the measures had been put in place "on a precautionary basis" but there had been no change to the threat level in the UK.
A Downing Street spokeswoman said: "The intelligence does not suggest there is any change in the threat level here but on a precautionary basis we have tightened up border security, particularly at our juxtaposed controls.
"For example at ports people going through them will see increased car and truck searches, a bit more scanning of freight.
"They will also see an increased visible presence, for example at our juxtaposed control at Gare du Nord in Paris.
"This is about looking at what we think is appropriate given the incident, but is not based on any change to the threat level."
An additional police counter-terrorism officer has been sent to Paris to join the British team of experts there, the spokeswoman said.
The Foreign Office is working with UK embassies across Europe to keep Britons updated about the latest advice, No 10 said.
The UK's response to the massacre of 12 people during a raid on the Paris office of satirical magazine Charlie Hebdo was considered at a meeting of the Cobra emergency committee chaired by Home Secretary Theresa May.
The meeting was also attended by the Metropolitan Police and representatives from the intelligence agencies, although the decision to beef up border controls was taken yesterday in the aftermath of the attack.
The No 10 spokeswoman said: "In places like Calais or the Gare du Nord people can expect to see an increased visible security presence."
The measures would also be "at other ports" and "based on what the authorities and the Border Force think are appropriate".
The Joint Terrorism Analysis Centre raised the terror threat level to severe - the second highest alert - in August, and there had been no change.
The spokeswoman said: "The important thing to note is that JTAC has not changed the threat level, it remains at severe, and when it was changed to severe that already informs our response.
"So we were already operating on a basis of (an attack being) highly likely.
"But as a British citizen I want to know that if there is an attack in a neighbouring country that has port crossings into ours, you would expect our authorities to be looking at doing all they can to keep us safe."
Asked if the measures were aimed at preventing those responsible for the Charlie Hebdo attack entering the UK, the spokeswoman said: "Obviously we will be working with the agencies and doing all we can to stop any perpetrators or those linked with the attacks reaching the UK, but it is not ... based on anything specific that suggests that is likely."
She added that she was not aware of anything to suggest that there was anything to link the suspects to the UK.