As the EU does not want to do a deal on our future relationship anytime soon the UK must leave in March 2019 without signing the one sided and damaging Withdrawal Agreement they propose. We can then proceed to negotiate a free trade agreement with them if they want to. Many Conservative MPs are making it clear to the government that we will not support legislation seeking to prolong transition, nor will we support 21 months transition and large payments for no good reason. So far there is no sign of any deal better than just leaving. Extending our period under their control would take us into another 7 year spending period where the EU would not doubt want even more money from us.