"We are making a UK commitment to the long-range missile programme, a formal commitment alongside Germany, France, Poland and a couple of others," Healey said on the sidelines of a NATO defence ministers' meeting in Brussels.

"We will lead work to improve the integration and therefore the effectiveness of our European air defence systems," he told reporters.

France, Germany, Italy and Poland announced in July a push to work together to develop the missiles that have a range of more than 500 kilometres (310 miles).

Healey also said London was ready to deploy swiftly, if needed, British troops to Estonia to bolster NATO's eastern flank against the threat from Russia.

"We are boosting our support for Estonia, with thousands of troops ready to deploy rapidly to the Russian border," he said, according to his ministry.