Isil supporters have cheered the attack on Westminster, suggesting it was “revenge” for the UK’s airstrikes on the terror group in Syria and Iraq.

Followers on pro-Islamic State of Iraq and the Levant channels on the social media service Telegram posted messages applauding the knife-wielding suspect and called the attack “blessed”.

One said the UK was paying “blood for blood” for its involvement in the US-led coalition’s campaign against the jihadists.

One poster suggests “Our battle on your land is only just beginning” next to a photoshopped image of Big Ben being blown up.