Prime Minister Theresa May must stop pretending that her plan for the UK to leave the EU, known as Chequers, can work and she must stop the clock on the Brexit withdrawal process, Scottish First Minister Nicola Sturgeon said on Friday.“Now that the EU has explicitly rejected it, the Chequers pretence has to stop. At the very least, single market/customs union membership must be back on the table and the Article 50 clock stopped to avoid a cliff edge,” Sturgeon said on Twitter.