LONDON (AFP) - Britain will invest £48 million in a new chemical weapons defence centre and vaccinate thousands of British soldiers against anthrax, the defence minister said on Thursday (March 15) after the nerve agent poisoning of a former Russian spy in Britain.

"We are investing £48 million (54 million euros, US$67 million) in a new Chemical Weapons Defence Centre to maintain our cutting edge in chemical analysis and defence," Defence Secretary Gavin Williamson said in a speech.

Williamson said the centre would be based at the existing Porton Down facility, a secretive British army base which analysed the nerve gas used to poison former double agent Sergei Skripal and his daughter Yulia in the city of Salisbury on March 4.

Britain has accused Russia of being "culpable" for the attack.

The Defence Science and Technology Laboratory - its official name - employs 3,000 scientists across a sprawling rural site, and has an annual budget of £500 million.

It was founded in 1916 to counter German gas attacks in World War I, which initially involved chlorine and then mustard gas and phosgene.

In the 1950s scientists at Porton Down developed non-lethal CS gas, better known as tear gas, as well as the deadly nerve agent VX.

Given international conventions that prohibit the use of chemical weapons, research conducted at Porton Down is defensive in nature, according to the defence ministry.

"If we doubted the threat Russia poses to our citizens, we only have to look at the shocking example of their reckless attack in Salisbury," Williamson said on Thursday.

He added however that threats from chemical weapons in different countries, not just Russia, were "intensifying".