US wont sign a UK only trade agreement in case of EU exit

How many jobs would this cost, do you imagine? How much trade would falter once extra tariffs were applied to British goods beyond those applied to good from the EU? How much more would american imports cost in the UK once tariffs were applied in the other direction?

UKIP and the Tories keep spinning the line the EU does nothing for us and an exit would do no harm. Let's be clear. They're lying.