An extraordinary week stands ahead of us at Westminster.A week in which MPs will be asked to make a decision that could have consequences for decades.If the Terminally Ill Adults (End of Life) Bill for England and Wales becomes law, it would give people, in certain circumstances, the right to die at a time of their choosing.Scotland is also considering a change in the law on the issue too.It is a colossal potential social change, compared by many to the Abortion Act of 1967, the abolition of capital punishment, the decriminalisation of homosexuality and the introduction of gay marriage.Opinion polls suggest most people are broadly in favour of a change in the law and have been for years.But it is impossible to be certain how the House of Commons will vote, not least because MPs are not being instructed on how to by their parties, as normally happens.MPs have a free vote on Friday.Speaking to those on both sides of the debate who are trying to keep a track on the numbers, there is an acknowledgement that sentiment has ebbed and flowed over the last few weeks, with opponents of change perhaps gaining some momentum after the Health Secretary Wes Streeting came out on their side of the argument.It is, for so many MPs, an intensely personal moment.Their usual political compass bearings, party loyalty and a broad sense of being on the left or the right, count for little here.Instead, an experience in their own life, such as the loss of a relative or their religious conviction may weigh considerably.There are three groups of MPs on this issue.There are the unshiftably opposed, who won't chan ...