The threat of chemical weapons attacks on Britain's streets is getting closer and "is real", the security minister has warned.

Britain must face up to the possibility of a chemical or biological attack as terrorists relentlessly pursue new methods to commit murder, according to Ben Wallace.

In a stark assessment, the Home Office Minister said he sees plots where "the only limits to the ambition of our adversaries is their imagination".

Speaking at the National Security Summit in London, Mr Wallace warned terrorists continue to explore new ways “to kill us on our streets”.

"Chemical and biological weapons are marching in closer,” he said. “They have developed and worked on a better arsenal and we have to be prepared that might come to our streets here.

"Be under no doubt the threat is real,” Mr Wallace said. “Our open, liberal and free societies are easy prey to those that fear little and care even less."

“The better characteristics of our safe, free, democratic society are used against us”.

Britain's most senior counter-terrorism officer echoed Mr Wallace's warning that the threat must be taken seriously.

Also speaking at the conference, Metropolitan Police Assistant Commissioner Neil Basu said: "These things have been used on the battlefield, and what's used on the battlefield will eventually be adapted to be used on domestic soil.