Exit from Brexit - Legally Possible?

From Spiegel Online International - "Leaving Room for Second Thoughts, Experts Believe Exit from Brexit Would Be Legally Possible"

"Could the British government pull its Article 50 notification and halt the Brexit process in order to buy more time for negotiations? Legal experts believe that could be possible. The European Parliament has now applied stipulations to ensure that cannot happen".

Related -

EU negotiator says Brexit is 'a Tory catfight that got out of hand' and predicts next generation will return to bloc - as MEPs approve 'red lines', The Telegraph


Guidelines for a soft Brexit, Andrew Duff, Policy Network

Looking back, looking forward,  A farewell to Britain, The Economist's former Bagehot columnist reflects on Britain’s past, present and future