British Prime Minister Theresa May has hailed the work of the UK armed forces in response to the Salisbury nerve agent attack and "protecting the country from Russian intrusion" in her Christmas message.

“From playing a vital role in cleaning up after a sickening nerve agent attack on the streets of Salisbury, protecting our waters and our skies from Russian intrusion and strengthening our allies in Eastern Europe, striking at terrorism as part of the global coalition against Daesh [Isis], and along with our US and French allies sending a message to the Assad regime that we will not stand by while chemical weapons are used, as they were in April on families, including young children," May wrote, according to The Independent.

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“Time and again you have stood up to aggression and those who flout the rules-based international order. You should be incredibly proud of all that you do – just as the whole country is proud of you," reads the message.

She warned of "new challenges" lying ahead, adding she knows"you will continue to meet them in the same way you have always done. With courage, determination, resilience, ingenuity. Qualities that are as vital now as they have ever been."