Dear [MP's name]
I am writing to you today as a member of your constituent to pressure the government to "freeze" exports of anti-crowd gas, riot equipment and so-called "rubber bullets" from the UK to the US. British law requires exports to be suspended if they are used for "internal repression", and this is the case in the US with police using 'excessive force' against peaceful protesters. Government records show it grants export licenses worth millions of pounds in the sale of said arms to the US - but the government's own rules say such exports should not go ahead. This action should be taken alongside a public condemnation of Trump's use of force against his own citizens from the UK Government.
Yours,