Could a junior coalition partner scrap nuclear submarines?

If the Greens joined a Labour-led coalition, would Labour allow them to scrap nuclear submarines?

Junior coalition partners can surrender policies, so participation in government would not ensure that the proposal was implemented.

The follow-up changes the premise from a party governing alone to participation in a coalition. The Liberal Democrats' experience with the Conservatives provides a caution about how much a junior partner can secure. The argument is that surrendering prominent policies in office can damage that party's subsequent electoral support. On that reasoning, a Green commitment to scrapping submarines would not determine the policy of a coalition government.