London - Foreign Secretary Boris Johnson said on Thursday that the UK will probably join the United States in further military action against Syria if asked to do so, whether or not Parliament gets a vote on it.Johnson said it would be "very difficult to say no" if the US sought British help for a military mission against the forces of Syrian President Bashar Assad.British lawmakers in 2013 rejected a request by then-Prime Minister David Cameron to authorise UK airstrikes in response to Assad's use of chemical weapons. Britain is part of an international coalition targeting the Islamic State group in Syria, but has not taken military action against Assad.Asked if Parliament would be asked to approve any new military deployment ahead of time, Johnson said "I think it would be very difficult for us to say no. How exactly we were able to implement that would be for the government, for the prime minister."Chemical weaponsParliament will be dissolved next week ahead of Britain's June 8 election, so lawmakers would not be able to vote on a request for military assistance before then.President Donald Trump ordered a cruise missile attack against a Syrian air base earlier this month in response to Assad's apparent use of a banned nerve agent against a rebel-controlled area.US officials have said further attacks are likely if Assad uses chemical weapons again.Johnson's remarks appeared intended to signal to voters that the Conservative government is tough on security and defense. He contrasted the stance to that of opposition Labour Party leader Jeremy Corbyn, a foreign-policy dove who wants Britain to give up its nuclear weapons.Writing in The Sun newspaper, Johnson called Corbyn "a mutton-headed old mugwump" with "no grasp of the need for this country to be strong in the world."