I write to you in your capacity as an MP who voted Remain in the Referendum.
May I please ask that, before voting on the triggering of Article 50, you bear in mind the following points:-
1. The triggering of Article 50 is not just a procedural step in the UK leaving the EU. Is is of critical importance. According to the wording of the Article, from that moment the UK surrenders all unilateral power to decide its future relationship with either the EU or the Single Market.
2. Whatever opportunity is given to either the electorate or Parliament to vote on any finally negotiated Brexit terms, the only possible outcomes will be the endorsement of those terms or their rejection, which will still leave the UK outside both the EU and the Single Market.
3. The Referendum was expressly Advisory and Consultative (see House of Commons Briefing Paper 07212, section 5), designed to advise but not direct you on your decision.
4. It has been an established principle, at least since the time of Edmund Burke, that MPs do a disservice to their constituents if they attempt to mirror popular opinion rather than to exercise their own judgment on national issues. Debates on the death penalty are a clear practical example of proper exercise of judgment contrary to popular opinion.
5. The recent Supreme Court decision, although based on narrower points of law, reaffirms that parliamentary sovereignty is essentially distinct from popular sovereignty, with the clearest implication that MPs have a positive duty to exercise individual judgment.
6. With hindsight some Remain MPs may regret having supported the decision to hold a Referendum out of excessive party loyalty. Please do not compound this error by voting to trigger Article 50 on the same grounds.
7. MPs have been reflecting on the merits and demerits of the UK in the EU for decades, while the electorate has been subjected to merely a few months of intense and often misleading lobbying.
In all these circumstances, the wisest course would be a postponement of the triggering of Article 50 to allow for a cooling-off period of say two years, during which the electorate would gain a deeper understanding of the likely consequences of Parliament following their advice. At the end of that period, in a calmer and better informed environment, Parliament should decide on the right course for the UK. You will not be thanked by the electorate for having taken precipitate, irreversible action if, as is possible, public attitudes to the EU change as understanding deepens.
I urge you not only to exercise your own individual and independent judgment on this crucial issue, but to encourage all your parliamentary colleagues to do so as well. This is your true duty to the electorate.