Lib Dem leader Sir Ed Davey has said he is "minded" to vote against an upcoming bill to legalise assisted dying.
MPs are due to debate proposals to give terminally ill people in England and Wales the right to choose to end their life.
The bill was introduced by Labour MP Kim Leadbeater after the prime minister said he would allow a free vote - meaning Labour MPs can choose based on their own conscience rather than having to follow the party line.
The issue has split Parliament, with MPs divided by ethics and practical concerns.
Sir Ed - who is also giving his MPs a free vote - warned that elderly and disabled people might feel pressured to end their lives if they felt like a "burden”.