Donald Trump announces his plan to negotiate a free trade deal with the UK after Brexit. Talks can begin in 2021, once the Brexit transition period is over, a letter to US Congress states.However, Trump's administration says the UK must abandon "unjustified" food standards before a wide-ranging deal between the two economies can be agreed.MPs, charities and health campaigners are worried that the US will demand UK market access for food products of a lower standard than what the UK currently accepts.Chlorine-washed chicken, hormone-injected beef and food containing maggots, rat-hair and mould are just some of the imports post-Brexit Britain could receive from the US.