For all its shortcomings as an institution for scrutinising new legislation and holding the Government to account - and I've spoken and written extensively about those shortcomings! - Parliament does actually spend quite a lot of time and effort pouring over draft new legislation. Over a period of months, MPs and members of the House of Lords spend dozens of hours between them debating the detail and likely impact of a Bill. And Ministers spend many hours on their feet, seeking to explain and justify their intentions.
And yet, despite all this often laborious activity, it is still possible for important - even devastating - consequences of a Bill to go unnoticed, and for ministers to somehow fail to mention those (intended) consequences when fending off the legitimate anxiety of MPs or peers. Take the Immigration Bill, currently nearing the end of its passage through Parliament after fifteen sessions of line-by-line scrutiny by a committee of MPs, and four lengthy Committee Stage sessions in the Lords.
One of the Bill's key provisions - one that has been of great concern to many MPs and peers - is the replacement of the current system of basic Section 4 welfare support for failed asylum seekers who are unable to leave the UK for medical or other reasons with a new mechanism, to be known as Section 95A support. There are some important (and regrettable) differences - including a lack of any appeal against a refusal of Section 95A support. Until now, MPs and peers have been assured by ministers that Section 95A support will be available to any failed asylum seekers who have a genuine reason for not leaving the UK immediately, such as being heavily pregnant.
Last month, however, sharp-eyed lawyers at the Asylum Support Appeals Project (ASAP) were astonished to read a five-line paragraph buried away in a 20-page document, quietly issued by the Home Office in January. This states clearly that the new Section 95A support will only be available to those who apply for it within 21 days of their asylum claim being finally refused (or within 90 days in the case of those with children).
This is a fundamental change. So I tabled a parliamentary question to the Home Office, asking how many single adult failed asylum seekers were granted Section 4 support in 2015, and how many had applied within that 21 day period.
And last week, I received the answer: 105 otherwise destitute failed asylum seekers were granted Section 4 support last year, 42 of them on the basis that they were unfit to travel for medical reasons (including six heavily pregnant women). Yet only six of those 105 men and women had applied for that support within 21 days of their asylum claim being finally refused.
In other words, more than nine in ten of those without children who were granted Section 4 support last year would have been denied that essential support, had the proposed new system been in place. So the Bill will leave vulnerable people - including pregnant women - homeless and destitute on our streets. And, not only have ministers failed to take the numerous opportunities presented to them to spell that out, but they have repeatedly denied that is their intention.
This is no way to make legislation. Ministers should be open and honest with MPs and peers about their intentions, so that they can be properly challenged. I will continue to do all I can to make that happen.
Caroline Lucas is the Green MP for Brighton Pavilion