The vote, which is due to take place around 2:30 p.m. (1330 GMT), is expected to be extremely close, with those on both sides of the issue voicing confidence.
As things stand, proponents of so-called assisted dying have the edge. When Members of Parliament, or MPs, last voted on the issue in November, those backing assisted dying won by 330 to 275.
Since then, the Terminally Ill Adults (End of Life) Bill has been scrutinized, leading to some changes in the proposed legislation, which is being shepherded through Parliament by Labour lawmaker Kim Leadbeater rather than the government.
Divisive issue
In opening the debate, Leadbeater relayed how she had heard hundreds of stories from people who saw their loved ones die in traumatic circumstances.
“Not supporting the bill today is not a neutral act. It is a vote for the status quo," she said. "And it fills me with despair to think MPs could be here in another 10 years’ time hearing the same stories.”
Proponents of the bill argue those with a terminal diagnosis must be given a choice at the end of their lives. However, opponents say the disabled and older people could be at risk of being coerced, directly or indirectly, into ending their lives to save money or relieve the burden on family members. Others have called for improvements in palliative care and greater investments in hospices to ease suffering as a better and more moral alternative.
Diane Abbott, a veteran left-wing Labour lawmaker, urged MPs to “speak up for the voiceless one more time, because there is no doubt that if this bill is passed in its current form, people will lose their lives who do not need to, and they will be amongst the most vulnerable and marginalized in our society.”
Passions were running high outside of Parliament where hundreds of people gathered to make their voices heard.
Supporters were dressed in clothing emblazoned with the phrase “Campaign for Dignity in Dying,” while opponents held up banners urging lawmakers not to make the state-run National Health Service the “National Suicide Service.”
The vote is potentially the biggest change to social policy since abortion was partially legalized in 1967.